Birth Control or pregnancy?

Patient: As a 17 year old, I started taking birth control in December because of really bad pain leading up to my menstrual cycle. I missed a pill which wasn’t a big deal, made up for it, then ended up missing another one and stopped taking it all together. I tried starting over once I started my period again (I had another period because I didn’t take the pill right) and I ended up being on my period for two weeks after stopping. It’s been a month since then, as in 31 days, and I have yet to start my period again. I normally have a 29 day cycle. Is this just because of stopping birth control or could I pregnant?