I've had UTI's with my pregnancies and didn't have any symptoms. When I told my younger sister about me having no symptoms she said she always knows right away when she has one because she starts feeling really sick with body aches and fever like symptoms. I was surprised to hear that, I thought symptoms were only painful in the urinary tract with an infection down there but after reading your previous responses and from my sisters experience, I would say that's certainly why you're feeling this way.
Having C-sections is a very painful recovery but mostly abdominal pain and you should be feeling much better by now with 3 weeks already passing, especially with this being your second C so I would say the symptoms you have are from your UTI. It will take a few days for the antibiotics to really kick in, take your pain meds (vicodin) if you have any still. It won't harm your nursing baby and should provide some much needed relief until your antibiotics have really kicked in. Good luck and hope you feel better soon!