UTI Not Going Away, Dr. Has Me On 2 Antibiotics at once?

I've had this for over a month and I'm very uncomfortable with the frequent urination and burning, so I went to the Urologiest yesterday and he has me on 2 antibiotics at once, plus he gave me a shot for a third. What if that doesn't do it? What is next? I apparantly have a hard to kill strain of bacteria and I'm very afraid it will go to my kidneys. I'm under medical care but so far it's still here... Also the meds they gave me for pain is not doing anything. This bacterial is tearing me up and won't go away. Wha'ts the next step? Also is it safe/normal to be on 2 antibiotics at once?