Hang on in there. Don't think of all the interminable "future" ahead of you. Just think about making it through the day, or night. Or if you can't manage that, the next hour etc.
That's how I'm making it through right now. If not hour by hour, minute by minute. Celebrate every new day as a victory against that "damn dog" that's sitting on your chest and suffocating you.
Do at least one thing you enjoy every day. (Unless, as 227 said, it's keeping severed heads in a freezer. Because, then.... Dude...)
The feelings you talk about are the depression's Negative Bias in play. Everything looks bad when you're depressed. Even internet kittehz look bad. Recognise that is what it is, and keep this thought
firmly front and centre.
You are not in your right mind. Like you don't drive when you're drunk, don't make life-changing or ending decisions when you're depressed. Your reasoning faculties are out of whack because everything looks bleak, even when they aren't.
Get help. From your family - with your family history, this is probably one of your family's worst nightmares. Let them in and try to help you. They want you to trouble them, because they would prefer you to be around to be "trouble".
Get help professionally. If someone isn't working out for you, try someone else, if you can. Try explaining this. Doctors are also people, as are psychiatric professionals. They should recognise one therapy does not fit all. And at the end of the day, asking for help may stop you from feeling this bad.
That hope is something I repeat to myself everyday. Because if I can make it through this day, tomorrow might be okay, or at least better than today.
Resume - Dorothy Parker Or I could always kill myself
tomorrow. Every day is today though, and tomorrow
is another day... (Yes, I know... trite, but in this case, apt.)
Celebrate today.