Mommy, can I have a snack?

Kiernan is making me mental with his eating habits lately. He just won't eat well. He starts to eat, comes off, screams, goes on, comes off, screams. Sometimes I can only calm him down by letting him suck on his soother for a couple of sucks in between mouthfuls of milk. Someone wondered if he was actually hungry and I would wonder the same thing, but it really seems like he is. I think part of the problem is he gets inpatient waiting for the letdown because once it really gets flowing he generally doesn't come off anymore... unless it's to catch his breath. So it's a fight at almost every feeding except the ones in the middle of the night. But what choice do I have? So far we haven't found a formula that works for him, and as hard as I try to pump (I even rented an electric pump for a week to see if that would help) I can't get enough out to even give him one bottle a day, let alone several. It's really starting to get to me. Maybe I'll start to refuse to feed him until he hasn't eaten for at least 3 or 4 hours to see if he'll eat better. I don't know. I think that ideally, he wants the milk to come RIGHT away, and I also think that he'd be happy having a few ounces every hour instead a nice good feed every 3-4. He just wants to snack all day.
He's fabulous, but man is he difficult sometimes. :P