I got a positive/peak OPK on the 14th at 3pm. But by 10pm the same day it was negative as well as the day after that. According to my apps that means I ovulated the 14th, 15th or today (the 16th)

I started having watery CM the 14th and cramps the night of the 13th and still do today. My cervix was in a fertile positive yesterday. My problem is that my BBT is not matching up. Any opinions?