I feel like throwing up

Everytime I eat or something I feel so nauseous. I haven't thrown up at all but I've been having this feeling for about 2 weeks. Idk what it can be. I'm 3 days late on my period my boobs hurt so much but idk I don't want to think I'm pregnant I want to see if there's something other than pregnancy causing this. I just turned 18 so that's why I'm trying not to think of pregnancy