G.B.
You may not be making enough milk for him. I do not believe that he needs anything for at least a few more months. He should not be needing anything.
You do realize that cereal and baby food has no nutrition right? It is simply for thickening to teach baby to chew and swallow.
It is not for food. For nutrition. Formula and breast milk are the only nutrition a baby gets. That other stuff is basically filler, not nutrition. So please don't feed it to your baby at this young age.
Kids in child care up through school age are not allowed to go over 4 hours without being offered a large snack or a meal. So feeding your baby after 4 hours is totally normal. Not abnormal. Baby's don't sleep all night, they don't go all night without feeding, they might if they're one of those that love to sleep but most baby's don't. They wake up every few hours to eat.