Since the suicide hotline # is circulating around Twitter, I just want to say: that may not be what helps you. If it doesn't help, if you get endless hold music & a disconnect like I did, don't let that be your sign that you've now tried everything and it's truly hopeless. Ok?
There's no one solution to a loss of desire to live. Where I'd suggest as a place to start is to find the calmest person you know who cares about you even a little and just talk to them frankly about what's in your head. (That person isn't me, btw. I am not calm.)
Try anything these people suggest, even if it seems dumb or if you've tried something very similar (but not exact). If it doesn't work, you can say, "Okay I honestly tried this and it didn't work." Try to figure out why, try something else.
You will NOT be able to get out of this on your own, though, so try not to obsess over the trouble you're going to be causing others. They'd probably rather you not be dead, so just, rotate between as many folks as you can, and keep getting outside advice.
Some folks just won't have the spoons to help you out. Tell them it's okay and move on to someone else, even if it's someone you don't feel you "connect" with well. All that matters is that they're relatively calm and don't want you dead.
Resist the urge to endlessly describe your feelings. Human psychology causes anything that's repeated often enough to sound like truth (ask advertisers! They know!) Focus as much as you can on figuring out what to DO next. Even if it's just "okay first take a shower."
Your feelings matter, and trying to divine the *cause* of them can be helpful, but if it's purely random/chemical then no, that won't help at all. If it's to do with guilt, etc., talking can help you untangle the strands, but focus on cause & on what you can change.
If none of this helps, try something else. Just keep trying things. Wish I had better advice than what's kept me around this long, but mostly I just wanted to say, that number is there, and it's good, but it's not The Answer, so don't give up if it isn't helpful.