Urination problem in puppy?

I have a 3 & 1/2 month old black lab. He is doing very well at housebreaking. The last four days, when I take him out to urinate, he squats, urinates normally, then squats two to four more times as if he is trying to urinate, but doesn't. I thought it might be a bladder infection and started him on some Keflex. He's had 3 days worth (the normal human course for a simple UTI), but is still exhibiting the same behavior. He isn't urinating more or drinking more, so I don't think it is diabetes. He is otherwise acting normal. He is not acting sick in any other way. He isn't incontinent; he hasn't been having accidents in the house.

My vet is closed for the next four days, so I can't bring him in immediately (unless I go to an emergency vet who I don't know). Has anyone had this sort of experience?

Thanks!

Please do not treat at home without consulting your vet unless you are qualified to do so. What you give your pup now may interfere with what a vet would prescribe.

He maybe drinking more water than you think...puppys tend to engage in water play..they can super dilute their renal system by taking in toomuch water, sometimes it's alot of fun making the water in their bowl move so they tend to lap up more than they actually need.

He could still have a uti too...call your vet asap, most vets will take after hours calls. This is one of the biggest money making holiday weekends for vet's here in the US, many backyard grills will be in use and many pets are going to be eating things they shouldn't.

Maybe he's learning to mark? He's really young, but if it's nothing medical, maybe it's an option... Maybe he's covering the urine of another beastie. Does he choose his spots or does he squat sort of out of nowhere?