Mittelschmerz and late period

Elle • Identical twin girls, born 1/10/19
So I have mittelschmerz and can feel ovulation, I thought it was more common but I've never met anyone else who has it. Before I was on BC, it alternated sides and then AF would come two weeks later. I had been on BC for 18 years straight, and had gone to a 3 month-between-periods cycle the past 3-4 years. My husband and decided we were ready to start trying, so I came off this past month. I felt ovulation, had sex during the days on and around then (I felt it on June 8) and now period is a week late. All three tests I've taken are negative. (Spaced out q 2-4 days) I swore I felt a pinch or very mild cramping about 10 days later (right around time for implantation). Nipples extremely sensitive, like hard to face the water in the shower) and now breasts are sore. Sooo fatigued the past week or so. I'm confused by the negative tests though. First month off the pill.  Thoughts?