Nausea-pregnant?

Well I hate having to post this because I don't feel like hearing any hate but I need some help. Three and a half weeks ago my S/O had sex and I let him cum in me. Usually this isn't a big deal because I am on bc but we had just had gonorrhea shots (I had gotten a false positive on the sti gotta love unnecessary shots) and I started a new bc. As many will know the shot for th sti cancels out bc and then a new bc isn't active for thirty days. Well we had been good most the month used condones stayed safe but of course we both got super horny and were out of condoms. I was on my period but on a lule so it wasn't spewing so I said fuck me and we did and instead of having him pull out like I always have him do I told him to come in me. The next day my period stopped. It had only been going for three days mine are usually seven. At first I attributed that to new pill but now I am having constant boughts of nausea and cravings are worse than ever. I typically don't get hungry but now I am constantly and I've been peeing more than I have ever known myself to. Also I am having extreme mood shifts. I would take a test instead of asking but it is too soon for an accurate read so I was wondering if any of all could help me by saying if you think this is a possible pregnancy. Please help I'm really starting to worry now. And By the way he and I are both 18.