Ovulation testing - endometriosis

My husband and I have been trying for a baby the last two months. We bought an ovulation testing kit as I have very abnormal cycles and a high chance of having endometriosis - I’ve been having investigations for it and although last year the surgery came back Unclear, my gynaecologist and endometriosis specialists says it’s probably a 99.9% chance I have it and that I will need re surgery to confirm it. I have put the surgery on hold as I don’t want to postpone having a family. (And I only had a ovarian cyst removed June 2019 and don’t want them to re open the same scars for the third time just yet)

However, I have only been doing the ovulation tests for a month and every test came back negative (I tested everyday). I then randomly came on my period - does this mean I didn’t ovulate this month and only had a period? I have read that this can happen.

My cycles lately have ranged from 77 days to 30 days. Very abnormal, so you can imagine the stress I have when trying to find out when I’ll be ovulating.

My gynaecologist advised that if we don’t get pregnant within 6 months, for me to go in for tests.

Does anyone who has endometriosis have had difficulty getting pregnant or confirming ovulation and what were your experiences?