Why do I sometimes just feel like I don't have a right to exist?

I'm a loser, I'm autistic, and I'm a burden on my family. I've been suicidal many times, and while I first thought it was because of women being mean or cold to me, now I realize it's more than that. It's a deep feeling of worthlessness, not really knowing why I'm here, and I'm not allowed to have any happiness. That's why I want to die... because my existence is pointless.