confused

Hey guys, so I finally lost my virginity last Friday. He wore a condom, no I'm not on the pill, and he didn't climax due to the fact that I was in too much pain to continue. I have always had an irregular period and use apps to help track it. So far I was suppose to start on Monday and I feel like I'm having PMS pains (back pain, abdominal pain, nausea, and dizzyness) but i have also heard there's a bug going around my dorm. I know there's lots of factors and I talk to much but what do you all think? Could I be pregnant or just stressing myself out?