Brief bout of pain with bloody urine.

On Monday of this week I was experience pain in my back. If I made a circle around my waist, it would have been a little bit above my belly button. I wasn't sure what caused the pain, but I thought it might have been from some heavy lifting I had done at work the Thursday before. However, the pain did not begin until that Monday, and by Tuesday it was completely gone. It hurt to move my body, and it was also painful if I pressed on my back. On Friday night (around 9pm) I began experiencing discomfort and started peeing blood. The pain increased and I felt the constant urge to pee even right after I used the bathroom. By about 4:30am the pain went away and I was no longer peeing any more blood. The exact same thing happened a few months ago, minus the back pain earlier in the week. I went to the ER and they gave me antibiotics for a UTI. I haven't had any other symptoms, and the pain and bloody urine only lasted around 7-8 hours each time, then I felt perfectly normal again. Any advice?