In my case, the problem was minor - I had a large number of capillaries exposed in my vagina, near my cervix, and sex was causing them to bleed. The treatment was a
procedure called
LEEP, which luckily healed the problem. But at the same time, the doctor had to rule out cancer, polyps, fibroids, etc. and did a hysteroscopy and biopsy. So... could be "nothing" but worth checking out.