Help!!!! What should I do?

Courtney

Help!! I have not had my last period since march 16th and then may 19th I started but no blood is was this blackish brown color a little heavy on Day 1 then the next day just spotting and the next nothing! I have taken 3 pregnancy test but all come back negative! Help I don't know why this is happening! I am sexually active and are not on birth control but always use condoms.