WHAT COULD THE ISSUE BE?? In my 3 month old infant?

I have a 3 month old infant boy. From day one I did have him on sin advance & tap water( wouldn't poop)then sin advance with the nursery water, then doc changed to sim sensitive (nursery water w/ floride) and Zantac for acid reflux. After 2 months of giving him the Zantac with NO change the doc said he was allergic to the Zantac and changed to Prioliec. Still same issues with his reflux, and started pooping, then watery muscus poop, to not pooping again. I then myself switched him to Enfamil Prosobee was good for a few days (poop and reflux) THEN right back to the same thing! He fights his eating spits it back out @ me, has NEVER slept more than 2hrs @ a time. and acrhes his back pukes across the room! I AM TIRED of these doctors not really checking him out! They only thing they have done was switch his milk (after making them) and then his reflux meds now to Prevacid. He's a NON-STOP screamer (said he has a BAD case of colic! SO, he NEEDS help and the quacks woun't really check him out? I was told to try switching him to alimentaim from similac, or enfamil nuetramigen??? what if it IS a soy, milk, wheat, corn allergy? SOMETHING PEOPLE I NEED HELP!! it hurts to see him go threw this??