In the past 8 or so cycles that I've tracked, I ovulated between day 16 and 21 of my cycle. My cycles are usually between 30 and 36 days. I recently got back on my thyroid medication and am exercising and eating better. My last cycle was only 29 days. I started taking ovulation tests yesterday on CD15, and I think I got a positive?? Then I took another later last night and it was negative. Then I took more today and got another positive? On CD 15 last cycle I wasn't even close to positive. I don't know what to think