Menstruation problems?

I am almost three months out of my surgery and had no problems for the first two months. Now I was 1 week late, then had spotting for about 5 days, and have now had bleeding for about 5 days or so. I hear it can happen with sudden weight loss, but was wondering if anyone else had this problem and what they gyn might have said. I might also be pre-menopausal (I am 53). I do have an appt. with my Gyn on the 25th, but if I am still bleeding I do not know if I should go. Thanks.