Okay so a couple weeks ago me and a guy had unprotected sex. I know he finished but idk if some of it was in me or not. The way he talked makes me think he did. Well I am on the pill so my period was suppose to be last week and it was 3 days late and only lasted 2 days. It was not heavy like usual and mine are usually 6 days long. Well two days ago I got really nauseous at work and threw up a couple times. I was also feeling really light headed and out of it. I went to a small clinic and they said they didn't know what was wrong and gave me some medicine for the nausea. So I have not thrown up but I am having AWFUL cramps now and my lower back is hurting more than usual. I am always a tired person but I have also noticed clearish white discharge. I took a preg test but it said neg, however I would only be barely 2 weeks. Could I be preg? If not what could it be? Help!!