Please don't be discouraged! If he has always been a good sleeper ,then somethings up. He may be teething. I think that's the culprit most of the time. He may even be coming down with a cold. I know it's so hard right now having to deal with getting up at night. It will pass. I promise. I read another mother's message the other day that sounded just like yours. Her daughter was teething. When my daughter's had this behavior, I gave them a dose of Motrin or Tylenol before bed for about a week. It seemed to help.
Uh oh though. I'm sure he is getting very used to the nursing that many times a night. I really don't think it's necessary to eat that much at night right now. Feed him a good snack before bedtime. That is, if he's has started rice or fruits. But, it's his way to pacify . I don't blame him. Beware, it may be very hard getting him to stop (maybe not. hope not.)
He'll be back to normal again and you can get some sleep.