Hi. You don't say whether or not you have had any surgical procedures done. If you still have your ovaries, then you are still producing estrogen from them. That may have something to do with it. I agree with the others though that you should have it checked out.
When I first started taking T., the endocrinologist told me that I might have spotting at times, but had surgery before that ever happened. Even though I had everything removed, including my cervix, he told me to get exams to make sure that I didn't develop cancer.
It never hurts to have an M.D. assess the situation, and I think you will rest easier if you know what the source is.
sam1234