Figuring out DPO

Michel • Married 4-25-14, son arrived 7/6/15, daughter arrived 3/15/18!
I am trying to figure out how many DPO I am. I had a positive opk on 6-3, but my bbt dipped yesterday 6-4 and I continued to have EWCM, but a negative opk. bbt rose today as expected. Do I assume that I ovulated yesterday because of the temp or on Tuesday because of the opk? Thanks in advance!