I Have Been Having Problems With Bleeding (not Menstral) For

I have been having problems with bleeding (not menstral) for over 18 months. I was informed it was due to having a polyp and had it removed. However a few months later had to have another one removed. I had a coil fitted and after a couple of months the bleeding stopped. Had about 4 clear months, then Jan this year the bleeding started again. Also and my last 3 periods have been every 2 weeks when I normally have a 28 day cycle. Is there anything else that can be done apart from to keep having the polyps removed? I am 45 years old and general physical health is good but I am prescribed Priadel, Quetiapine & Venlaflaxine for depression which I have been taking for a number of years.