Hi there,
I have found for myself (and I'm sure everyone is different) that the milky cm is still before you O.
I have definate ewcm before I O and it looks exactely like an egg white and is stretchy like one too.
If its milky you'll probably find tomorrow it will become a bit more clear.
Hope this helps, I find cm is the best way for me to find my O day.
It wouldn't hurt to BD now anyway as they say its better to have the swimmers there before you O.
Good luck, J