Hi
Coincidently I just read about this phenomenon in "what to expect when you're expecting". It says that some women find they cannot pee despite feeling like they have a full bladder. It is because the uterus is usually sitting just in the wrong place and blocking the urethra. It says it is something to talk to your practitioner about. It mentions them moving the uterus by hand and some other stuff.

Sounds like it has fixed itself up for you Caddie, but I'd be mentioning it to my practitioner.