I'm amazed that you've been taking Gabapentin for that long. I tried it a long time ago and had terrible side effects. Sounds like your Microbiome in your gut is out of wack. Do you take Probiotics?

I tried gabapentin for a few months and it didn't help the pain and I didn't like the side affects. Alot of weight gain!

About to start Nortriptyline but I think the side affects of this can be awful till it settles including diarrhea but I do believe everyone handles each drug differently

Good luck in your search x