Bipolar Disorder Support Group
Bipolar disorder is not just a single disorder, but a category of mood disorders marked by periods of abnormally high energy and euphoria, often accompanied by bouts of clinical depression. This is the place to talk about your experience with bipolar disorder, learn from others' experiences, and find support.

Big hug.... I hope that you start to feel better soon......xo
I seldom take it anymore.... Very occasionally if I can't sleep..... Big hug
https://www.ehealthme.com/ds/gabapentin/depression/
As for weaning yourself off, you shouldn't do that without your Pdoc's guidance, especially with being on other meds,
Depression is a possible side effect of Gaba. Its an Anti-seizure med and is used off-label for Nerve pain. So hopefully when your off of it, your Depression will subside.
Take care.