This is pretty typical with Gabapentinoids. Gabapentin (Neurontin) is the namesake of the group, which includes Pregabalin (Lyrica), Phenibut (OTC Supplement) and others seem to be appearing on the market as well, but we're not talking about those here.
Gabapentinoids are pretty notorious for the rapid tolerance they produce. If you use Gabapentin at recreational-level dosages, whatever those are for you personally, 3-4 days is generally when you're going to hit the wall. When you hit this wall, it's gonna be ~72 hours for your tolerance to get close to where you first started.
These are drugs that really need to be used strategically to achieve maximum benefit. Don't binge, don't take crazy amounts and always work drug-holidays into your overall plan.
For what it's worth, it seems that the drug's analgesic effects are going to be more long-lasting than the euphoric/recreational effects that you're describing. There are people who have taken Gabapentinoids for years who still report positive benefit. Even for these people, drug holidays are (like with many other medications, especially those used for pain) likely going to be a major factor in drawing out the length of benefit.
If you really need these for pain, I would suggest not messing around with the dosage. Keep it as low as is needed to control your pain. I'm happy to answer whatever other questions you've got, so feel free.