25 Weeks Pregnant with Blood in Urine?

Yesterday i noticed there was blood in my Urine and i have noticed it a few times after that but sometimes when i wipe there will be a tiny bit of blood on it. I went to the doctors thinking it was just a Urinary Tracy Infection now she ordered blood test on my Kidneys. She never told me what for or what it could be. It really worries me that it could be something really serious or that i could affect my baby, I'm wondering if this has happened to anybody else or what it could possibly be.