What Causes A Delayed Period With Negative Pregnancy Test?

Hi my name is Laura and I was wondering if you could possilby help me. I was on birth control for a year and just recently stopped taking it in the middle of Dec. I had a period normally about a week after I stopped taking it but have not had one since and its going on 2 months. Me and my fiance have been having unprotected sex and I took 2 pregnancy tests and they both came up negative...is it possible I still ma be pregnant?