My boyfriend and I have tried dry humping fully clothed but one time I was in my underwear while he was in his underwear and pants. We did not really rub each other genitals but if that has happened it might have been for 5 sec. My leg was in his genitals though. He told me he ejaculated and I was also "wet". A week from that day I have been having growling, back pain and acne (I usually have acne and back pain before my period but my period is in more than 2 weeks). Should I be worried that I might be pregnant?