Hello and welcome to HCM.
Thank you for your query.
A increased urge to pass urinate and not being able to pass normal amounts of urine despite of having an urge of a full bladder could be due to two primary reasons.
1. An infection, as stated by you, a UTI
2. Pressure from surrounding structures on the bladder, that gives a sensation of a full bladder and the urge to want to empty the bladder
Thus, my advise would be to visit a doctor for a physical examination followed by non-invasive investigation like ultrasound
of the abdomen and pelvis, to rule out any abnormalities of alternate structures.
A urine analysis would also greatly help in directing us towards a possible UTI or ruling it out.
The itching around the anus is most probably due to the hemorrhoids, but you will have to get this checked as well, in rare cases, poor hygiene resulting from hemorrhoids in female patients has resulted in the occurrence of UTI's.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you.