I Am 65, Female, In Very Good Health, No Medication

I am 65, female, in very good health, no medication and take vitamins. My hair has started to fall out (even the hair dresser noticed there was a difference in the quality of my hair). Then, last weekend I had two nose bleeds...haven't had more than three in my entire life. Don't feel run down and I eat pretty well almost always. What can be causing this?