OP, I've come back from despair. ADs don't work for me, talking therapies don't work for me (I completely dry up and can't speak in therapy-type situations) and I've gone to bed praying never to wake up again more times than I can count. It's survivable.
Without any details it's difficult to give any advice at all, so all I can do is tell you what works for me. And that's as someone up-thread said, take it one day, one tiny step at a time. Make a list of things that give you some degree of pleasure, even just a little bit. I'm deliberately not saying 'things that make you happy' because that probably seems out of reach right now. But go for the small things, and ones that aren't harmful! A cup of tea, a favourite TV programme, a walk in the park, whatever. And make yourself do one of them, one day at a time, until it gets to be a habit.
You say you know what you want from life, but not how to get it. Well, I'd say don't dwell on what seem like long-term out-of-reach aims right now. Establish some habits of doing nice things - it'll get you into a better place. Then you can start looking realistically at what you want and break it down into what you need to do, medium-term, to get there. And if necessary, at what compromises you need to make - spending your life pining after the perfect life you can't have is much worse than going for (and mostly getting) the life that'll do, even if it's not quite as you'd hoped.
I won't go on about what my issues were/are, but just to say that about 15 years ago I was a complete mess in terms of relationships, friendships, job, housing, money, weight. Things are far from perfect now, and I get moments of feeling utterly alone and wishing my life had worked out differently - but I know the moments will pass, and they don't swamp me like they used to.
I hope this helps - I'll be thinking of you. 