My Ball Python Is Being Weird!!! HELP!?

I have a ball python. I'm not sure the yet, but I'll have that checked by a specialist very soon. It just ate a few adult mice (3 to be exact, but the guy I went to has been raising pythons for years. I trust him.) He ate them two weeks ago, and I've been giving him warm water shelter to bathe in when he want. But today he began to rub up against a small resin tree in his cage and the seemed to actually urinate liquid. I'm freaked out because snakes should only be secreting dry waste. What's wrong with my snake?!