1 Day Positive OPK

Elizabeth • I`m Elizabeth and 41 year old mother to a 2 year old.
Has anyone ever had only 1 day of a positive opk?  I took the test Thursday and it was positive but Friday it was not. I assume I ovulated Friday because my bbt rose (and since the Thursday test was positive). But then....this morning (Saturday) my bbt was back down. I guess if it starts to rise tomorrow all is good?