Positive OPK but no EW CM

Maddie
I'm on my second round of Clomid. Got a positive OPK yesterday (CD18) & today (CD19). No egg white CM though. I THINK it might of been EW CM CD17 but that was it. It seems to be watery but light now. However my cervix is low & open! 
First round I did get EW CM. 
Do you have to get egg white CM to conceive?