17 and pregnant

I've missed my period and told the guy and he's like not worried about it? Even tho he came inside me. I'm not trying to stress but it's hard, I'm never late, I feel sad because if I do end up pregnant he won't stay around. 😔 I'm not sure what I should do, and he hangs out with other girls and he just sometimes reply to me and sometimes ignores me. I don't really want him involved honestly, is that okay?