Cm after my period vs during my fertility window

I have a 28 cycle and a 3 day period. I notice that after my period ends I have a lot of egg white cm and my sex drive is very high. During my fertility window (according to the app and opk strips) I have a lot creamy white cm and a low sex drive. I’m starting to think that’s y I’m not getting pregnant. The consistency of my cm has changed during my fertility window. I was think that the ejaculant is changing my ph therefore changing my cm but not sure if that’s true or not. I don’t get egg white cm durning my fertility window. Not sure if it’s possible to ovulate days after a period either. I use the opk strips on cycle day 12 like the instructions recommend. Any advice?