Had peak reading on clearblue advance opk on cd 5&6. i continued to test and had no more peaks. could this mean that ovulation happened that early?

May be false positiv: A normal ovulation will not happen on cycle day 5 or 6 (assuming you are counting day #1 as the first day of menstrual bleeding). Occasionally an ovulation predictor kit will be inaccurate because of other hormonal problems. Your doctor may order a Progesterone blood test around cycle day 21 to help determine if ovulation truly happened.