No period for 3 months negative tests

So for the past 3 months I havent had a period and everytime I take a test it would have a very faint line then a negative test a couple of days later. I am not trying to conceive but very forgetful with the pill and would forget to take on time but dont want to continue taking the pill if I am pregnant. Has anyone experienced this and have any suggestions on what to do as doctors dont have much to say about it and was wondering if people have experienced the same.