I would recommend speaking to your medication prescribers about the side effects of the meds or combo of meds has on your body and any potential pregnancy. I stopped taking birth control 4-5 years ago after it was explained that a side effect of one of my meds made getting pregnant virtually impossible while taking it. It could be that you are experiencing something similar or as others have stated perhaps your not having sex during your fertility window. But at the end of the day if you want children somewhere down the line don't be afraid to ask the professionals.