Note: Sam has some dark suicide-related thoughts in this, and I feel the need to clarify that his views in this are based in guilt and self-hate and are not fact. Calling someone selfish for contemplating suicide only further blames the victim.

Depression takes many forms; makes itself known in many ways. It can be blaring: a neon sign that follows you as you walk and taints every one of your interactions with palpable pain. Or it can be quiet; insidious: painful in an even deeper sense in that even when you think you're fine, you're really crumbling inside and dying a little each day (and really, you've gotten so used to it that you've forgotten what normal feels like). It can be self-injury; it can be forgotten meals; it can be days spent doing nothing when the thing you wanted to do most was something.

The depression Sam falls into after Jess feels like it was a long time coming. It's a culmination of many things: of a broken childhood, of an absent and functioning-alcoholic father, of what it had cost Sam to escape to college and what that escape had ended up costing him. Costing Dean. He'd been so selfish. He knew it. But he'd wanted, so badly, that freedom he'd been fantasizing about for over a decade. For probably, if he thought back hard enough, even longer than that.

And then Jess died. And he knows, he knows he shouldn't be this wrecked, because as much as he desperately, desperately loved her, he'd fallen a little too hard, idolized her a little too much. And he knew that. Hell, she'd known that. It hadn't driven her away; it'd endeared him to her. He wasn't possessive. Didn't get controlling. He just loved too fiercely, too passionately, built Jessica up in his mind into something she wasn't.

Because she was never his freedom. She was never his absolution, his exoneration, his gate to love and a life of choice. She was just Jess. And somewhere along the line, he'd been swept up by her and the things he'd so desperately wanted for so long, and he'd forgotten that.

It's systematic. He has nightmares. Nightmares for weeks that leave him shaking, breathing heavy, and gripping at the sheets in violent cold sweats. Nightmares that jolt him bolt upright in bed, Jess' name hoarse on his lips. Dean pretends not to hear, doesn't bring it up, and Sam's desperately grateful for it. It lets him compartmentalize. It lets him cope. The nagging thoughts that he could have, should have done something are bad enough on their own, and they're even worse because he knows they're true. Where it had mattered, about the one thing that had been most important, Sam had lied. And Jess? Jess had only ever been honest with him.

It's distraction. Sam's very absent the first few months they're back on the road. He zones out when Dean's talking to him. He misses cues. He's lost in his head, lost in some dark place swirling with guilt and memories. He's lost count of the number of times he's been jolted back to reality, and the only thing he can answer Dean with is a lost "huh?". The guilt he feels is crippling, all-consuming, it makes it hard to breathe and makes him want to throw up if he ever lets himself dwell on it too much. He should have never let himself into Jess' life. He'd known, somewhere, in the back of his mind, that it wasn't going to end well. He'dknown, and yet. And yet.

It's sporadic; unpredictable. The littlest things set him off; set him right back to where he was a month ago. The color of a passing woman's dress. A beautiful summer day (he knows he enjoyed those with Dean long before Jess even existed to him, but Jess is gone and Dean is not). Staring into a fire too long. Having urges that he'd never, ever mention to Dean, urges involving fire and gasoline and getting payback on himself for what he'd let happen to Jess. He's not suicidal. He's never been. But sometimes he can't help but fantasize about how much better the world would be without him. He'd never do that, though. He's already left Dean once; he's not sure he could do it again, and he's not sure if that's for Dean's sake or his own.

It's bizarre. Not just the nightmares, but the visions. The hallucinations. He sees Jess, sometimes, and it gets harder and harder to hide from Dean the more it happens, because he freezes when it happens. Stops dead. Stares at, what's from Dean's perspective, thin air. You can't exactly brush off that sort of thing, and you can't exactly hide the full extent of the pain in your eyes from someone who's known you since birth. He wonders if Dean thinks he's losing his grip on reality. He wonders if Dean's right.

It's anxiety. It's Sam awake at two a.m., breathing ragged, his head in his hands, clutching uselessly at his hair because he's afraid. Afraid of life; afraid of the future. He hadn't felt this fucking lost or scared since he'd found out monsters were real, because it feels like everything's falling apart, now. It feels like things won't be okay again. Because now he's tasted death. Of course mom had died, but he'd never known her, had he? Not like Dean had. But he knows what a brush with it feels like, now, and it unearths some buried fear in him that he hadn't let himself feel for years. He's afraid to lose Dean. He's fucking petrified of it. And with the work they do? It's a much more distinct possibility than losing Jess ever was. And one of those things had already happened.

It's aggressive. They fight. There are shouting matches. There's bitterness; anger; pain. As terrified as he is of losing Dean, he's afraid to let him too close, too. Because Dean? Dean means an infinitely larger amount to him than Jess ever did. If Jess was a star, Dean comprised constellations. And he can't lose that. He can't. Because a blot in the sky is one thing; your entire world being punched black is another entirely.

It's slovenly. Sleepness nights and apathy that spreads like rot aren't exactly conducive to good habits. He doesn't sleep well. He drinks too much coffee. He doesn't shower as much as he should, and the ominous circles under his eyes grow darker with every passing day . Dean's concerned, Sam can tell. But Sam's too far deep in his own misery to even care much; to even put the effort forth to bridge that connection with Dean and maybe accept a little help. Because he doesn't want help, not really. He's pretty sure he deserves this. God, who the hell is he kidding? He knows he deserves this.

It's fragile. Sometimes apathy can turn to agony like a switch being flipped. And Sam – Sam feels so alone, so fragile, so guilty and wrong and broken, that eventually one day it all spills over. Dean's gone, off interrogating some witness, and Sam? He cries. He cries hard. It's like a dam spilling over – once it starts, he can't stop it, and his lungs ache and his throat burns and he can't breathe but he can't stop the tears either. And then he caves. He calls Dean. He's not sure what he might do if he doesn't. Part of him is afraid Dean will chastise him, tell him to grow the hell up, get over it, maybe even mock him because he can't keep his emotions inside like Dean does and of course that's emasculating, right? Dean doesn't make fun of him, though. Sam's voice is raw, tight, trembling, and when he chokes out the words he does – I need help and I'm afraid I might do something and I need you – Dean goes dead silent, before telling Sam to stay there and give him five minutes.

Dean makes it in four.