Can I be pregnant? Not having my period?

My period is late for 3 days. Today is May 1 and I was supposed to have my period on April 28. On April 26, my partner and I were fooling around. He came but not inside me. We wiped the *** off with tissues. Minutes after we were cuddling and I started to masturbate. Also I am a virgin. Is it possible that I am pregnant in that way? Or is it because that I had a hard work out on the 29th that left me feeling dizzy and nauseous. Or maybe is this because of stress? I am currently having a hard time with my relationship. I usually have pain in my inner thighs, headaches, back ache, mood swings and a tingly feeling down there when I am about to have my period. And I did but I am not sure if this is because my period is coming and if it is then why am I still not having my period? and also I feel dry down there.