I Am 65 Years Old And Haven't Had A Period

I am 65 years old and haven't had a period since I was 50. I am on hormone replacement for 15 years with no apparent problems. My doctor felt that it was safe and good for me to continue. Two weeks ago i had what seemed to be a period for about 2 i/2 days. The blood was not red but brownish, and seemed a little putrid. Should I be concerned? I do have an appointment with my gynecologist in a month