Living with my Boyfriend

I am eighteen going on 19 in October and I want to move in wth my boyfriend. Mostly because it'd be a lot cheaper and id rather live with him than have to deal with a roommate that I don't trust. We've been together a year and a half and he's met my family and everything but my family keeps saying I'm too young and it's not appropriate. They make me feel like an idiot sometimes. Sometimes even say that I'm making stupid decisions and I'm not thinking properly. This really messes me up because I already think that way about myself. Just last week my mom said that he could move in with my family because I wouldn't be able to go back to school and they know how difficult distance can be and then she came around and said that she didn't say that at all :( she told my whole family that I came up with that idea so now they are all yelling at me and saying I'm stupid and young and that I'm not thinking right. I really just want to run away. Everytime I come home and stay I want to kill myself because they make me feel this way. What should I do?