Hi J.,
14 lbs is big for 2 months old, is he tall? If he is, that is probably OK, but your pediatrician is concerned about your baby becoming and saying overweight. Here's why- Formula fed babies usually learn to self regulate and you can usually feed them what they want, when they want, as they usually will only "hunger cry" when they are no longer satisfied. Since formula takes longer to digest and requires less intake, they usually eat less often and less oz than a breast fed baby. Babies stomachs are only as big as their fist, so if 5oz is bigger than your son's fist (at 2 months old I'm almost positive it is) then you're streching his stomach and making him require more to feel full. She is trying to get your son's stomach to shrink back to the size it should be so he requires a reasonable amount of food to feel full. You need to give his body time to adjust.
To quiet your son's hunger cries and your nerves, Try this:
Feed him 4 oz at a feeding, when he starts looking for food- don't wait until he cries. The next feeding, try to distract him for 5 minutes, 10 if you can, then feed him. Keep bumping up the period of time that you have between feedings, in even increments. He is used to taking in more, so you have to wean him off of it. You wouldn't want someone to cut you off of an entire meal cold turkey, would you? Same goes for the baby :)
Also, taking in too much food can cause reflux, or aggravate it. Think about it like this- have you ever eaten a huge meal then gotten heartburn afterward? The muscles that keep the stomach closed do not work as well when they are stretched out and pushed on. Hope this helps!