Uh oh...?

I'm just about ready to have sex for my birthday and I just inserted pre seed. Now that I've done that, I'm cramping. In my butt kind of also. Sorry for the TMI. I have had positive opk's for the past four days and finally today my CM is a cloudy (very faint) and watery. Anyone else going through this? Why would I be cramping? What is going on???