I didn't feel it ?

Kelsey • I have been trying to conceive my second child for two years... I am so happy that it has finally happend!
So this is my first month using OPKs 
I started my AF on the 6th and ended the 9th. 
I got a positive opk on the 10th.
What's odd is I can usually feel when I ovulate. ( this is my first period since June due to taking a BC shot then using a 28 day cycle of BC pills to get my period back) 
Now I'm 6dpo and I have been feeling a little cramping ... But I still haven't felt myself ovulate. 
Does anyone have any input ?