Baby corn snake wont eat, what am I doing wrong?

I purchased a baby corn snake at the end of July. He was a easy pet to take care of, eating a thawed pinkie weekly (every Tuesday), up until September 8th. When I fed him on Sept 8, and I checked on him the next day, he had threw the pinkie up. I figured it may have been too big because I did everything else the same. But the pinkie wasn't much bigger than the previous ones. I tried to feed him again on the following tuesday, and he wouldn't eat. And I have been consistent and tried to feed him every Tuesday since and he won't take it. He does have a white belly and I can see some black, maybe feces, in the middle that hasn't went anywhere. I am out of answers and I am starting to worry that I am starving him. I don't think its because he's shedding because he shed the week before he threw the mouse up. He is also starting to slither all jagged like, not smooth like he used to. Please help!!