I had never had this problem before, until the last 10 days or so. During that time frame (with the exception of last night, thankfully), I have woken up at 3 or 4, soaked, and unable to go back to sleep.

I have no idea what would cause this, and the weirdest part is the consistency; not only from night to night, but also how it coincides with your experience.

I doubt this information is of any help to you, except that you're not the only one.