Late period, positive ovulation tests and laparoroscopic surgery

Hi everyone, I had my last period on the 17th of June. It was for 5 days as normal. I should've been due for my period a week ago and it didn't show. I had a laparoroscopic surgery on June 28th to remove endometriosis, I bled for multiple days afterwards.

Anyways, last week for 4 days in a row I got positive ovulation tests. We're in a same sex relationship and received one donation over the 4 days.

I never miss my period, and I've never had ovulation tests so positive before.

Anyone got any idea why I could've missed my period but got super positive ovulation tests a week after my period was due??