I Had A Endometrial Ablation About 15 Years Ago. No

I had a endometrial ablation about 15 years ago. No periods since until August 2014. Had mood issues and black stringy discharge, every few weeks, lasting a day or so. Doc says I have thick uterus and did d and c. In Jan of 2015. Says I shouldn't have issues for years to come. Heathy 50 year old and no signs of menopause in blood work or otherwise yet. Now I have black stringy discharge again. So will I have to have another d and c every 5 months or do I need to do something else? Calling doc tomorrow but need piece of mind today