Since you also faint, take a
pregnancy test and see. Other
causes are hypothyroidism, cervical dysplasia, cervical polyps, cervicitis (infection/inflammation of cervix), vaginitis (infection/inflammation of vagina), cervical and uterine cancer, uterine fibroids, hormonal imbalance as in polycystic disease of the ovary, use of blood thinners, genital ulcers, STDs and stress.
The best thing would be to consult a gynecologist and try and assess what is the cause of your problem.