I had this, and it got quite painful before the end - and not just during my periods...my surgery was actually precipitated by an ovarian cancer scare, but in the end it turned out I had a bad case of adenomyosis and while my ovaries were quite scarred I didn't have cancer

It is your body and your decision to make, but it is only early Jan, if you have the surgery now you will be back on the bike by spring.

FWIW, my specialist told me that the only trustworthy way of diagnosing adenomyosis was after the uterus was removed. Now my surgery was in 2008 (and no one thought about adenomyosis at the time), so perhaps diagnostic tools have progressed since that time.