I had pain on the right side on the 21st, then pain on the left on the 22nd. Then a couple days after that I had pain right in the middle. I had EWCM for the 22nd and 23rd.
You would really need to do bbt, unless you can pinpoint ovulation signs and symptoms.
For ex: this cycle i got positive opk cd16 17 18 (had ovulation pains on right side and cm, at that point i new i was ovulating) and 19, negative cd 20 temperature shift on cd 21. Taking your temps basicly tells you that you have already ovulated, 1-2 days ago. So i assumed(well i no) i ovulated cd18, the egg lives for 24 hours so thats why i would still have a positve opk on cd19 and it should be negative cd20. You can guesstamate,( i would say you probably ovulated the day after the positive afternoon, but you do need more things to go by. Do you get ovulation pains? Did you get EWCM during one of those days?
I had this same prob so I did bbt and it was very accurate and I found it easier to deal with than opks.