I am right there with you. I feel like it took a good 2, or more likely 3 weeks for my body to become fat adapted on my first Whole30. I am right on day 20 now, so I hope it's the same or better now (it's almost 5 years later now, so I'm sure my body doesn't fire up like it used to). But I felt the same as you, after it was finished, I stuck to the general template for quite a while and I got even leaner and my energy was excellent. I started taking it for granted and cheated or splurged a lot more often as the years went by until this past year when i was completely off of the wagon. I'm hoping I can get back on track and lean back out...and then not fall into the lackadaisical trap again.
How have you been feeling since you started? Better, worse, same?
I know what you mean about missing how you felt when you were on the post Whole30 meal regimen. I mentioned it on my log, but aside from the fact that I need to drop some weight that has quickly latched onto me, I really want to get back to feeling as great as I did on a daily basis when I was eating a lot cleaner and not drinking as much. I'm on day 18 now, so hopefully I will be there soon. Good luck.