I have this problem too. To me it happened after an UTI, I guess I remained nervous each time I had to go pee. When I am really stressed I can go every 15 minutes. Even when not so anxious, I still go 7-8 times per 24 h though I do not drink a lot of fluids. To me it comes and goes and while being anxious I have the annoying sensation I have to pee all the time.