Overactive bladder or all in my head???

[Overactive84]

Hi - sorry for the long rant. I’m a 33 yr old male with no prior health issues. I take 1mg propecia for hair loss (been on it for a few years).
6 months ago I started getting urge to urinate frequently. Not extremely excessive but more than normal. I would just feel the urge. I can hold it in easily for hours. No issues with stream or flow. Symptoms lasted 2 weeks and went away on their own.
They have come back now. Have had Multiple urine tests, std, blood, digital prostate exam and ultrasound of kidney, bladder and prostate. Nothing has been found. Doctor has said it’s just an irritable bladder. This has cause me anxiety and given me insomnia. The doctor gave
Me Valium to help me sleep. I’ve only taken it two days very low dose 2.5mg. Hasn’t really helped sleep but I’ve found that my urinary symptoms have completely disappeared. Has the Valium causes the bladder muscles to relax or was this all in my head and Valium has just taken the edge off anxiety???