@lfisher66 I'm glad to hear you're not down and out, and you are able to work. It's too bad you've chosen to discontinue Gabapentin so early. The name of the game is to titrate up in dose. That is what a doctor should recommend. It can be challenging to hang in there while the dose slowly increases before determining if you've found relief. Maybe you'll try again one day. Pregabalin (Lyrica) and Gabapentin are both are recommended for Fibromyalgia.

It sounds like you're doing all the right things for your muscle cramps...stretch, walk, exercise, magnesium. How about your hydration? Are you drinking enough water throughout the day? How about Epsom salt, warm baths and massage?

I found this Clevland Clinic article on muscle spasms. It might be worth a read:
https://my.clevelandclinic.org/health/diseases/15466-muscle-spasms
The only other thing I'll throw in is that all the tips and tricks for muscle cramping can be used, is that the addition of learning how to strengthen your belief in your abilities to learn how to effectively deal with stressful situations is clutch. Especially living with chronic conditions like fibromyalgia. You mentioned cognitive behavioral therapy (CBT). I'm sorry it's difficult for your scheduling purposes, but please don't give up on it.

@pacer3702 had a good question about EMG testing. Have you had a nerve conduction study or EMG testing to rule out other causes? I too experienced muscle cramping and twitching from neuropathy. What have your doctors ruled out?