Trying to make it work, but damn these times are hard

Why do I just hurt people like it doesn't matter? It really does, and I try and stop myself but I always end up the same.. Getting shouted at for being a dick to someone or crying because I can't reserve what I've done. I really do care about everyone, but I make silly mistakes that make people think differently of me, I'm so surprised I have a boyfriend and I'm even more surprised I have friends. I always mess people about, I've lost good friends this way and it kills me, I don't want sympathy because I know I bring it on myself, but holding back tears when thinking about the past is hard. I've been so selfish so I'm trying to apologize for everything I've done wrong, hopefully it will make people despise me that little bit less.