I had my period right before bunion surgery and then two days post-surgery. is that normal and how can i predict when i will ovulate next?

Stress: Esp surgery can throw off your cycle use ovulation predictor test kit and give it a month or two to straighten itself out.

Depends on cycle: If you are saying your period was continuous during the time before and 2 days after the surgery, then that's normal. However, if you had a regular menstruation before and then had another menses following, that may be due to stress from having the surgery. A lot will depend on your normal cycle. But, at 40, also talk to you gyn because it may be coincidental and early menopause sign.