What Causes Vaginal Bleeding And Clotting With No Pain Or Discomfort?

Ive had constant vaginal bleeding for a few months now. There is no pain or discomfort just constant heavy bleeding and sizeable bloodclots and I am not on any sort of birth control. I know they don't usually like to do the exam when a women is on her period but I plan to make an appointment very soon. My question is what can I expect to happen given my current circumstances?