unprotected sex first time, please help

Kass
Had unprotected sex 15 days ago for like 30secs-min and I'm really nervous if I'm pregger or not. I was on my 2 day of ovulation. He said he didn't ejaculate but I know pre-cum can come out without him even noticing. I also took plan b 5 days after.  I took a test 2 days ago (the 13th day after unprotected sex) it said negative. I've been constipated, farting a lot, durping, feels like I'm hungry all the time. I think I have Been stressing myself thinking I am so I believe it. I don't know . I think about it and then I'll have to go pee 2 mins later. Should I be worried about being preggers? And I'm suppose to get my period in 2 days. No hate please please help !!!