I had sex for the first time on the 8th of November. It was around the time I should've gotten my period (the month prior was 5th of October to 12th of October). Said period never came so on the 22th of November I took a pregnancy test, it was negative. I felt bloated and my abdomen was swollen. Nothing else though. I took another on the 25th and it was also negative.

Finally, on the 8th of December I started cramping and I started bleeding. It was much lighter than my normal periods, and lasted about 6 days.

My abdomen is so swollen I can no longer suck it in (I had a pretty flat stomach before this I'd say?). Needless to say I didn't have a period this month.

I can't really say I had other symptoms of being pregnant. An occasional headache here and there but otherwise I'm pretty normal.

What could be this?