Could this could be a miscarriage... Help please

Hey guys! I've posted before but I wanna make sure.. I had a normal period, on the pill and it lasted 5 days. Awesome. I was without a period for two days and yes I did have sex during that time, and before my period, and we did not use a condom or pull out. Then after two days without a period I was having cramping really bad, worse than a period cramp, I was feeling sick day and night, almost threw up, and had all these pregnancy symptoms.. Then I had a really heavy period.. It was bright red, and faded to dark red. I didn't miss a day on the pill either. So out of curiousity I took a test. First one was taking forever and was a faint positive. Second was negative. On day 7 of my period again.. I went to the doctors and explained. She said it could be a missariage of my birth control since I've been on the pill since February.  I took a test again and it's negative.. Now I'm 5 days late for my next period and have no pre period symptoms...