Yep, loads of us have bladder issues, either going too much/frequently; feeling that you are busting to go and only getting a dribble, raging retention; not being able to feel bladder at all (not feeling it and retention are my issues).
Request/get a referral to a Urologist - I ended up having a melt down with a locum over my issues before I got a referral (more to get me out of the room I think).
Urology can assess what’s going on and advise/help you out. From memory, there was the peeing into their special loo set up that measures how much and flow rate (they do go out of the room for that); then they did an ultrasound to see how much is left in your bladder - at this point they nearly had a melt down and rushed me off for scans on my kidneys because the retention was spectacular (no damage to Ks), back at Urology they inserted a catheter (no problems there) to drain my bladder and since then I have been using intermittent self catheterisation (nowhere near as bad as that may sound) to keep on top of things.
Blood tests and UTI tests won’t show what is actually going on with your bladder - Urology is the best place.