Could i be pregnant or what do you think? please help!?

Hi. I haven't had my period since the 1st of November, and my periods are VERY irregular. One the 4th of decemeber my bf n I were fooling around. I had thin sweatpants on but he didn't have anything on. I'm not sure if there was pre. My bf says he urinates everytime after he s to clear any leftover sperm. (He d 12 hrs prior too this). Now on about the 20th of january I have had back pain n cramps, i figured I was getting my period like usual. On febuary 1st, I got my period, or atleast I thought. It lasted until early today. It wasn't very heavy bleeding so I'm not sure if it was my period or if its bleeding from pregnancy? Do you think I'm pregnant or if I just got a light period this time around?