sore nipples, vomiting. Can i be?

Okay so not last Saturday but the Saturday before I got sick for the first time. I at first thought I was getting sick cause of stress. My boyfriend and I have been having problems for a couple weeks now. Then I got the flu and I thought well it could be the flu. Now though, I no longer have the flu. I talked to his mom, who studies nursing and has for years. She said I shouldn't still be getting sick. But I throw up at least once a day. As of around three days ago my nipples have been so sore. The only way I can explain the pain is to say have someone biopsy your nipple, stitch it, then try to cut the stitches out. It hurts that bad. And yes I know that pain cause I got a biopsy done when I was seventeen. I've also though, had diarrhea. I saw somewhere that, that is a pregnancy symptom. But it seems unrealistic to me. I mean we had sex three days after I finished my period. I'm not saying its impossible because I've messed my birth control up the last few months and now I don't know when I ovulate or even if I do. My period has been at random times these last few months cause of my birth control mess up. We use the pull out method, which most say works but I'm still iffy about it. He doesn't precum, don't ask me why but he really doesn't. I read like not even ten minutes ago that doggie style apparently helps you get pregnant, and that happens to be our favorite position. I just, I started throwing up I wanna say two or three days after we had sex. I mean I don't think he ejaculated in me and I hope he'd tell me if he did but I don't know what to think. My friend just had a baby and says I should take a test in a few more weeks. I'm not gonna complain if I am, well I might but not because I'd be having a baby but because I hear it hurts your hips. I just don't wanna take a test if it doesn't seem likely.