Self mutilation

I really don't know the best way to describe it but here goes: Whenever i get mad or frustrated I feel this insane feeling in my head and i just have the urge to hurt myself in anyway imaginable. It started in 6th grade but it is a LOT more frequent now (I am 20 years old). It really started up way more, that i noticed, was when i found out I might not be able to have children, which is a big deal between myself and my husband, because we want a big family.. For example, whenever my husband and I argue, i instantly start hitting myself, usually in my stomach. I just, I know there is something wrong with me, i just don't know what. I've tried the whole therapist thing and it didn't work out, but I'm making another appointment because honestly, i am really starting to scare myself with it. I can only describe the feeling i have as being insane or mentally crazy in some way