Pregnant on the pill??

So I've been taking the pill now for 3 mouths, doc said start taking the day I start my period soo my period was 5days late and very light but started the pill, the last 8weeks I've been so tired went doc she told me (as well bloated too) she thinks I could be pregnant! I didn't listen but now my boobs are killing me and I'm sick every night!! I done a cheap test and negative so can I get these symptoms while on pill?