False positive OPK possible?

Michelle

Hello, I normally ovulate on cd14 with a 28 day cycle but this month I tested with clear blue advanced on day 7 and 8 with empty face results, then blazing solid smiley face on cd9. I tried a different brand on the same day and got a negative. Have now tested with clear blue advanced this morning CD11 and back to the empty face. Did I ovulate early or was it a false positive?? I know I'm not supposed to use fmu but I did. Should I keep testing or am I out this month? 🙁