I think both medications are hard on mental functioning.

Amitriptyline in the elderly poses anticholinergic effects on the brain. Depending on your age, that would be something to consider. But your dose is not high, and many others get used to it.

Based on what I have seen on these boards, gabapentin is a serious drug that impairs cognition for most. (I've never used it myself).

Things like Aleve would not affect the brain that you would notice. Other antidepressants may or may not cause side effects.
SSRIs are less sedating than amitriptyline.

I use tramadol, and I could never drive or walk around on that..I reserve it for bedtime. But many can tolerate it well.
You'll just have to try other things if you are highly motivated to change.

Discuss tapering off the gabapentin with your doctor...I'd try that one first. You'll need medical supervision for that. As you taper down, you can see if your mental functions improve.