Early Ovulation?

Hey everyone! I went off birth control on September 21st. I finished my pack and waited for my period to come. Had my period as expected on on September 25th, lasted 3 days, per usual, and then 3 days later on CD 6, I felt ovulation pain in my right ovary. I have been charting my bbt and my temp spiked the next morning on CD 7. I started taking opk tests, as the chart says I'm reaching my fertile window, but all coming back negative (REALLY negative!) Is it possible I actually ovulated that early in my cycle? I've been on BC for 12 years, eithout any breaks, so I don't remember a lot about my "normal cycle." Any input appreciated!!