You might have some re-bound anxiety from taking them, but I highly doubt you'll have any real withdrawal symptoms. If Gabapentin works for you as a mood enhancer or god knows what it does... I mean I love Gabapentin but some people just cant get off on it haha. It might improve your mood and I always get really sleepy 5 - 6 hours after taking it.
4 days is not enough time to produce a physical dependency and exhibit withdrawals upon cessation. Maybe some rebound anxiety and psychological craving, insomnia, but no real physical withdrawals. You would have to be taking daily doses for at least 4-6 weeks before reaching the danger zone.