It sounds to me like he just had a lot to drink! He's just a wee little lass and all that water vs holding it in that tiny little bladder was more than he could stand. My 10 lbs, 15 mth old girl will drink and drink when she plays and then pee every hour. Normally she can hold it at least 4-6 hours when she does her normal daily drinking. When she drinks more than her usual she goes frequently enough for my DH to say "again!?" when she stands at the door barking to outside. I wouldn't think anything is wrong unless this continues another day or two ater being back to his normal drinking pattern. However, I am not a Vet and you can always call into your Vet's office and run the question past his/her staff. They'll give you some sound advice! Good Luck with your little one!
