Nah- give him a few days. If he eats a lot, he may not eat for a day or two after that. Keep tabs on how often he defecates. It'll come in handy later. If he poops every 3-4 days, then you notice he hasn't pooped in 10 days, start to worry. Not eating is better than not pooping!
He sounds kinda temperamental now, but should calm down in 30-40 days. He'll freak out for a while again when you move him into the dresser. It's normal. He should get a vet check in general, though (parasites especially -blood work and fecal exam)
There are rare exceptions, but virtually all Sav's are wild caught. A captive bred Sav. would probably cost $200 Kinda pricey. All my guys are wild caught, and the vet should be able to kill any "African hitchhikers and stow-aways" for ya.
Keep posting his behavior -there is some great help here. Don't forget...soon you'll be a SOURCE of info. Help the next guy when you can! 