A significant number of us have gone through depression as well, so we do (to a point, at least) get what you're feeling. And things do get better. It's hard but if you can push through it you'll be much happier for it.
And that's all I can really say without knowing more details. Keep it up, you're doing good. Things will get better in time. And talking to people does help. It doesn't matter if they're not close enough to make a profound difference, even just venting on random forums to random internet people is better than bottling stuff up.
Venting is apparently part of my problem.
D'you have anyone you feel comfortable talking to in person about whatever this is? Being alone sucks, and our brains don't handle it well. If you genuinely don't have a friend-group, that's likely a major part of the problem and should be rectified with a quickness.
I would view this situation as another dangerous obstacle in your path, with an end goal of survival and fixing the factors that made it happen. If there's no way out that pleases everyone involved, choose the one best for you, though that can include helping others.
I am in no way professional, qualified to give advice, or really experienced in dealing with particularly big problems, so take this with a grain of salt.
As for not having a friend group, it's the part of the proble. I thought I have a friend-group, with few people who I could really rely on and one certain female person which I though I could rely on even more, but in the end it turned out that I can't, at all. And it's not even about losing specifically her, as I thought before, it was complete utter shit but I thought I could get through it - but I got betrayed so damn fucking hard I can't even rationally explain why did she and they did it to me. I feel like I'm missing an very important thing that could explain it all. As for the way out which pleases everyone - there could be, but really it's pretty much impossible and also proably doesn't please everyone, and I'm not even sure if it would please me. And I'm not really in the position to choose.
And it's not even the whole problem, my family basically stopped caring about me existing, my mother is kind of in trouble too and we aren't exactly on the best terms, school just keeps throwing shit at me and people can't seemingly understand I'm having trouble and aren't exactly in the mood to do anything else than just pass, serveral other people want me to do stuff like I did before and are very suprised to hear that I can't and are giving me a lot of shit for "letting them down", living sucks and thanks to the modern social networking shit I keep seeing how amazing and great time everyone else has. I'm also kind of required to act like nothing major is happening, but I swear that one day I'll snap.
I've never suffered from depression (yet, there's still a good number of years in me (I hope)) so I can't exactly understand how you're feeling except by what other people say, and even then it's not perfect.
But from what people that have been suicidal have said, it's not something you want to go through with. Most people, upon doing something like jumping off a bridge, have a moment where they realise all their problems are fixable on the way down, and then they realise that it's too late to go back and undo what they just did.
And, to paraphrase that guy's (I don't remember who, go me!) lecturer, You can save people. It's OK if it's only one person, and it's absolutely fine if that person is yourself.
Their problems aren't really that fixable once it's too late to un-jump. As for the depression - I totally know what is happening to me, I've been through one already, for quite different reasons and it's proably because of that I'm again stuck in it, since I lost basically everything that brought be out of it at first. Seriously, I know all this talk, I know the reasons, I know that I shouldn't, I know it gets better, I have experience getting through it, kind of... but it doesn't get easier. I don't see an reason to live anymore, and it simply... hurts to live, I just want it to stop.
You'll probably be pretty glad you didn't kill yourself in a few weeks when your brain chemistry comes back out of depressed-by-rejection-by-girl mode, what with death being irreversible, and there being plenty of other girls (now or in future). If you don't decide to try to never fall in love again.
I seriously wish it was just that simple as being rejected by a girl. It is proably what was first piece of this whole spiral of shit and caused a good bit of it, but it's not.