Should i take my daughter to the hospital!?

My daughter is 14,, in the past 4 months, we have been to the doctor four times. They diagnosed her with Probable UTI. All the urine dips came back positive in the office but in the lab it was negative. We took her to a urologist, they found nothing on the ultrasound. She has to go back for a flow test, but the earliest appt. for that was in three weeks. Now for the past three mornings she wakes up, pees, and hysterically cries, saying that she has to go so bad but only a few drops will come. I honestly don't know what to do about this. The reg. doctors found nothing, the uro's cant have her back for a few weeks and she's hysterical right now. I don't think she's crying from pain, more fear and uncomfortablity. I wonder if it has something to do with her bladder muscles? Should i take her to the hospital? Please help!