I have similar low back problems, oab, and stress incontinence, and have been on many of that same cocktail of drugs. I got off each of those, and now just take meloxicam, the generic of mobix (or mobic, can't remember the brand name). It takes a lot of the pain away, or at least makes you not notice that you're hurting.
The oab still sends me to the bathroom a lot, and pull ups catch any small drips from the stress incontinence, but I don't hurt and still have a clear head.