Hi, may I ans

Okay so I've always had unprotected sex with this guy, the last time I had seen him was the end of Nov. I have been on birth control since October of last year. In december I was three days late for my period, then a weeklater I had started again, then 2 weeks after that I started again. In January, a couple weeks before my period was due, I was spotting red for one day. This month, I was 2 days late for my period,it seemed like spotting the first day I thought I started. Then the next day I am now spotting brown. Also I was diagnosed with gallstones in November, I have been taking medication since then. I have also been taking Vitamin C and D and also cranberry pills to prevent UTI's. Other than that I just feel right pregnant, bloated, my lower stomach is like hard, i've been having back pains, gassy, always burping, and most times i throw up in my throat. what is going on?