Urinary Tract Infection... Help!

So I went to the doctor last week because I had dull cramping like pain in my lower stomach. Turned out to be a UTI.. Took my antibiotic twice a day for 7 days. This morning was my last one. Tonight around 6 pain started coming back. An hour later it's much worse and on my right side too. I call the on call nurse and doctor and went to urgent care. Turns out the UTI is still there.. I'm put on a different antibiotic for 10 days. I'm freaking out that it's something else like appendicitis.. This pain is horrible. I just want to be able to sleep tonight and take care of my 2 year old!! Anyone had one with this type of pain?? Help!