Hi, My Name Is Addy. My First Day Of Last

Hi, my name is Addy. My first day of last period was Jan 7 2016 it was an extremely light period on and off spotting until February 7 2016. A whole month!! It's now April 15! & still no period!! I have a guy feeling I'm pregnant! I am very intune with my body. While my hpt are showing a very faint positive the Dr office test are not. Despite telling them I know I am pregnant, they will not give me a blood test or run further testing. I am also on adderall 10mg once a day. My question is, is it possible that adderall is effecting my pregnancy test? Causing a negative? If not what else could be the problem?? I know I am pregnant!! I even look it! Thanks so much!