I’m so tired of my life

I’m the oldest daughter at home. I have a sister 13 year old which doesn’t do shit at home. Even the simplest thing. Which means that I have to do the dishes by hand every day when I come from college. And I spend like an hour doing them. I walk to college back and forth, and I’m responsible for my autistic brother when my mother and sister are not at home. I have to clean him when he poops himself, and it’s really stressful and depressing because I shouldn’t have to do this. I do it because my mom does it all the time so I should help her a little bit. But I’m tired. I should be more independent at this age (20)(21 next month) but no... I don’t have a car, don’t have a job and my income it’s 100 dollars Every two weeks. I’m so depressed right now, I know some people have a harder life than me, but that doesn’t make my life less hard. :/