Hello Sandra,
I am 58 as well and been in post menopause for a couple of years. I have read and heard that our bodies can still produce just enough hormone for us to bleed like that, especially if you are on synthetic hormones. I have used the bio-identical hormones and even they can cause break through bleeding.
Last year, I had the vaginal discharge that was red-tinged. I went to my doctor, they did some tests and an ultra sound, they have found a solid mass on my right ovary, but there is no vasculization in it, which is a good sign and my CA-125 is low, they want to do a biopsy of it, but, I have not scheduled one yet. I have not had any more bleeding or symptoms, they say I should get it done, but, I can wait to see what happens. I still, say that we can have these issues for up to 5 years or more until our bodies adjust and as I said, I have read articles that say the same thing.
If you are worried, then see your gyn, it is probably nothing, but, peace of mind is priceless.