Scared. Could I be pregnant?

Patient: Hi. A couple of weeks ago I was fooling around with a guy and we were grinding naked and his penis went half way in my vagina with no protection and I’m pretty sure there was pre cum and I have been feeling really weird since then. I got my period the next day which was a good sign but it went for only 5 days which is weird cause it normally lasts anywhere between 7-10 days. I have been getting cramps and headaches and nausea since. I don’t know what to do. Could I be pregnant??