I'm very sorry you're feeling so low. I'm in a similar position that you are in (no job, no school, no social life, no nothing). I can tell you this isolation will only make you feel more and more hopeless. You could try to find something that you really like or that you're good at... and think of it when you need a reason to get out of bed in the morning. Try to go out a little, even if you go only for a walk. Talk to your friends, it sounds like you need some support irl too...
It's important not to isolate yourself completely... Don't stop living, your life IS significant, you just can't see it right now. But it's the depression talking. You have to fight it.

Take care of yourself