baby smells like urine

I have recently noticed that every time my 11 week old pees, he immediately smells like urine. I don't remember this being an issue before. He currently wears #2 pampers. I tried huggies, same thing. He pees a lot. Seems like he is always wet. I changed him at 9am, pee smell went away. By 930am, he was wet again and smelled again. It's not a weird smell, just smells like urine. I spoke to his doctor, she said it could be something I'm eating (breast milk) or a new formula I am using (suplimentation). I changed his similac from Suplimentation to their regular formula. But it just doesn't seem like that would cause this. I asked about UTI - google search- but she said It's so rare, and I would noticed his pee being thick and dark. And it's not. Anyone have a smelly baby?!?!