Abnormal Pap Test

Hi my name is rosa.when i start takin birth control pills the dr do a pap test and came back normal 4 months after that i start having heavy bleeding for 2 months the entire month and i stop taking the pills .2 months later i was pregnant and when i was 5 weeks went to my ob and do the pap test again and a couple weeks they call me and tell me that my results cameback abnormal and send to the farmacy a antibiotics.now at my 6 weeks checkup the results cameback abnormal too and they tell me they dont know what is it.and i need a colocospy and biopsy i am 24 years old .they really need to do all his?its true they donth know why cameback abnormal? Thanks for your answer.