I took a muscle relaxer (Soma) when I was about 9 months off and it gave me very bad racing heart for two days. The setback was short-lived and no permanent damage was done, but it didn't help me at all for the issue I was taking it for (tense muscles in shoulders).
Urinary frequency and urgency are fairly common wd symptoms and will go away as you heal up. In the meantime, probably the best thing you can do for your bladder is go on a very low acid diet for a month or two--that would mean no alcohol, coffee, tea, soda, fruit or juices, vinegar or anything pickled, salad dressings, mayo, hot peppers/sauces, tomato products, etc. Acidic foods aggravate the bladder lining. Increase your water intake to keep the urine diluted so it is less irritating to the bladder. Try to find a bottled no additives spring water with pH 7 or very near that. Steer clear of cranberry juice--it's super acidic!
Two things that can help you with acid in foods when taken with meals are 1) 1 tsp baking soda in 1 cup water, and 2) Prelief, a product sold at Walgreens and online, which counteracts the acid in food. It is better to just avoid acidic foods altogether, but these things might help when you slip up or when you're not sure about the ingredients in what you are eating.
Also do what you can to relax and decrease stress, as the bladder muscles react to that with urinary frequency and urgency. Do pelvic, hip, and lower back stretches to reduce the tension in that area.
AZO is meant to be taken 3 times a day for the best relief. Often just one dose doesn't do the trick.
Over active bladder meds such as ditropan and vesicare may help, too, if OTC and self help remedies such as I have suggested have failed. Muscle relaxers such as baclofen may or may not help, but you may have to try several before you find one that works. And of course everything has side effects. So the best route to go is to is the natural route, by avoiding acidic foods and increasing water intake, and wait for healing, which will happen the longer you are from your last benzo dose.
Be sure to be tested for a UTI. There are OTC tests available.
Hope this helps!