The pain meds can affect hormones involved with ovulation for up to 3 mos. Since the surgery was after ovulation the first was on time. While the liver detoxes all the pain meds hormone circulation is lowered messing with ovulation. The 4 th period should see a stabilization of hormones and give you a better idea of 'normal'

Have you tested for pregnancy? :-)

It's also possible your ovulation is thrown off, this is your first ovulation after surgery.

You may not have ovulated which can cause a missed period. Stress can cause anovulation too.

Best wishes to you regardless of cause, this sounds unsettling and I really hope you don't need more procedure time!!

It can be unbalance of hormones... Let's wait and see...