OPK tested positive just for a day and half

Hi Ladies, I’ve been tracking my ovulation with opk 2 days after AF. I got a BFN for the first 3 days . I didn’t test on the 4th day . Tested on the 5th in the morning & got BFP & also at night . Tested the following morning & the control & test line was the same. Tested again at noon but it was negative. My cervical mucus changed from creamy to little egg white over 3 days . And it’s back to normal sticky scanty mucus. I don’t know if I ovulated or not since ovulation occurs 24 hrs after opk is positive but didn’t see a egg white after that. Is this normal ?