Rice Cereal

So I am very frustrated!!! We are all aware of how huge Johnny is and how he has always eaten more then his age says he should. Well in the last few days he is demanding even more. He has been at 8 ozs every 3.5 to 4 hours and now it was only 2.5 hours and he woke from his nap yelling at me, crying and Johnny doesn't cry, I tried everything, rubbing his gums, singing, Tylenol, teether and all of that, finally I broke down and gave him four ozs of formula and he sucked it down, but he doesn't go to bed for 2 hours and if i feed him all of his dinner this early he will wake early to eat again. I wanted to give him rice cereal tonight (since last night he did this as well, waking screaming to be feed) I called our pedi and they couldn't give me advise because they hadn't seen him yet nor could they give us an appt earlier then July 26th!!!!! They sent me calling three other government organizations before I got a very simple answer of "not until 4 months" but nothing I can do to help him. He is so big and growing so fast. I want to follow my instincts, but I don't want to make him sick either. He is changing a lot right now, as if over night, naps are shorter, waking in the morning earlier, needier, and much more hungry. I am ready to adjust for him, but I don't want to do anything wrong.