Since he's still not eating AFTER his shed, it may be that his home is not as secure-feeling to him as you have assumed. You might need to duplicate how the breeder was housing him (ie. much smaller accommodations).
*Also, EXACTLY how & when are you offering him food? This is more important than you might realize, especially if this is your first snake. They're not like feeding cats or dogs or birds- just not.
**Have you been handling this snake at all? It matters...a lot, for a "new" & non-feeding snake.
*** Anything else in the room that might be scaring him? Too much activity (any kind), little kids teasing him or hovering, cats or dogs lurking about...etc?