UTI pain but no UTI!

Janelle • First time mother. Baby boy Gabriel due 10/22/15. Registered nurse. Natural birth and parenting.
Hello! I'm 16w pregnant and this week I have had a lot of pressure and pain that feels just like a UTI, but I do not have an infection. I feel like I have to urinate really bad all the time with no relief when I do! I have felt round ligament pain and this is a much different feeling. I am eating super healthy with plenty of fiber and about 100oz of water daily. Any other ladies experiencing this?