His symptoms sound pretty severe for a piece of pepperoni & a cinnamon roll.
Is it possible he got into something? or ate a non food object? Xmas time there are always lots of things laying about, wrappers, paper.. etc.
Id take him to the vet to be safe if the pepto is not clearing it up, it sounds like something else is going on, my dogs get stuff all the time (kids) and they've never been ill from human food.