Birth control issue or possible pregnancy

In November I got my period twice. I was on birth control. The first one was for three days, after this I stopped taking birth control, and then a week later it was for 10 days. My period usually lasts for 7 days. After the 10 day period was done, my boyfriend forgot to pull out and I didn’t bother to take a plan b. It is now cycle day 37 and I have no period. I usually have my pet before then. Is this a birth control issue or possible pregnancy?