Hiya, I had a implant in my arm to stop

Patient: Hiya, I had a implant in my arm to stop me getting pregnant, I had it removed in September 2014, I then had normal periods, during February was on for 4 weeks none stop, I then had unprotected sex with my boyfriend on the 6th march and I havent had a period since, im not sure if its because im pregnant or because I was on for so long previously? Could you help me please? Also would a urine infection change the pregnancy test results? ,

Doctor: