16 years old and nervous..

Okay, well I have no one to talk about this with and I am really hoping for reassuring answers. I lost my virginty a few weeks ago. He only put it in once and then he pulled out because it hurt too much. This happened a few more times and no, we did not use protection and I know that's stupid.. but it just happened. Like I said, we barely had sex. It was for a few minutes at a time and I'm 99% positive that he went pee in between ejaculating. He never came inside me, once he pulled out, we were done. He never came at all those nights. I feel fine, never spotted, wasn't really even sore.. just shocked that I lost my virginity at 16. Anyways, one of the nights a few days after, we had a condom and he put it on, he went in me about twice and he said he felt like cumming so we stopped. He never did cum though. Anyways, about 6 days after, I spotted. I was TOTALLY freaked out. But, then we remembered that I also spotted randomly last month, too. Last month, I was a virgin and he only sometimes fingered me. So, that kind of reassured me. Usually, I start my period the last few days of every month and I usually get TERRIBLE cramps. This month, besides the sex, we didn't do very many other things sexually and it was only about 6 times that he fingered me. Anyways, it's May 27, the last week of the month and I haven't even had cramps. I haven't started yet. I feel as if maybe it might happen tomorrow or the next day, because I have had VERY slight cramps.. but Im not sure. My periods never start on the same day. Sometimes the 25th, the 27th, the 29th, the 30th. It's always different. The only pregnancy symptom I've had is an achy back. Do you think I could be pregnant though?