Thanks, all!
I still have a ton to learn about the medications... it's comforting that it's not all that strange to try multiple anti-depressants. I guess my frustration around it has mostly been that I haven't been able to get into a Psychiatrist, and also the length of time it takes to taper down and build up to a therapeutic dose on a new medication. It's a bit of a journey each time.
In any event... I'm going to research gabapentin a bit more. In the meantime, I'm working on therapy, getting enough rest (this is something that I always strive for, but I don't sleep well), and treating myself better (eating healthy, working to get some exercise in, etc.).