Onmynerves - Sorry to hear about your health issues. 5mg's of CDB via a capsule is almost nothing when you factor in bioavailability (see below) and when you consider you were taking the maximum amount of Gabapentin.

Bioavailability is the percentage of CBD that is actual absorbed and introduced into the body. Edibles have the lowest bioavailability with ranges from 4% - 20%. Sublingual (under tongue for two minutes) is much higher bioavailability with ranges from 20% - 35%.

Dosing it different for everyone, but you should start with a much higher dose (IMHO) based on the items you mentioned. I would start with 25 - 50 mg's of CDB oil (Sublingual) three times a day for a couple of days and increase as needed

Let us know how it goes and best of luck to you