bleeding for two weeks straight

Patrixia

im on the trust pill which is a combination pill. just two weeks ago i started my period again like ten days after ending my original period. ive been bleeding up to now and im getting extremely concerned

i had a check up with the obgyn and she gave me a pregnancy test; it came out negative. she also mentioned that i have an open cervix but im 18 and ive never had a child. any explanations as to why this is happening?