Dilemma...

I normally ovulate around CD21 (today is CD21)
Yesterday I felt a little under the weather and forgot to do a OPK
I've just done one now and it's super positive, I BD this morning. 
Do you think I'm too late?
Would once only be enough.
Feeling totally out already 🙈
I only started getting ovulation pains this morning & sore nips.