Polymenorrhea or bleeding from vagina more than once a month could be due to several causes such fibroids, adenomyosis, endometriosis, uterine polyps, hormonal imbalance, thyroid problems and bleeding disorders. It can also be a part of severe pelvic inflammatory disorder. STDs like Chlamydia and gonorrhea too can cause this.
You should get an evaluation done from a gynecologist and get these possibilities ruled out.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.