Pain and blood after sex

Okay, so I've had this problem for awhile but not sure if it requires me to go to the gynecologist. I've been sexually active for about 5 years now, and most of the time when I am on top it hurts my lower abdomen, in the same area you usually get cramps. I also sometimes bleed after as well. I've also found that when I use my vibrator, I sometimes bleed a lot, for a little while, even after using the vibrator, and I get the pain in my abdomen sometimes when I use that as well. Does this require medical attention or is this normal? Thanks!