Hello,
This is Dr. Christian. Welcome to JustAnswer. A few questions will help me get a clearer picture of this situation:
Thank you for the information. Here are a few possible causes for what you've described:
Unfortunately, there is not much to be done in any of these cases at home. It is definitely best to have him seen as soon as you can when your vet opens. An exam, x-rays and a urinalysis will be the next step. If he starts vomiting, his belly seems painful or he can't urinate at all then try to find an emergency vet that is open today. Waiting until tomorrow in that case could be dangerous and cause serious damage to his urinary system. If you have more questions please let me know.
Veterinarian
12 years of veterinary experience in medicine, surgery and behavior with exotics,canines and felines