Hi, and thanks for your medical question on eHealth forum!
Chances of pregnancy are less, and possibility of this being due to implanaon is more. 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 could also be due to an IUD implant (implanon) or due to oral contraceptive pills.
It can also be a part of severe pelvic inflammatory disorder. STDs like Chlamydia and gonorrhea too can cause this. Since a confirmed diagnosis cannot be given on net please consult your gynecologist regarding this. Hope this helps. Take care!