Baby cries after eating...

Sporkmoostipe

Long story short: he had been having very mucousy stools for about 2 weeks and Saturday night they were streaked with blood. He was in agony, screaming every time he had a bowel movement, and they were extremely frequent. Took him to the ER and after a series of tests, it was determined he had a milk protein allergy.

So, switched him to alimentum similac that morning after we got back from the hospital. He seemed ok for a little bit but now he is screaming after every single feeding. He'll straighten out very stiff and he just seems miserable. 

I'm waiting for the pedi to call me back right now....has anyone dealt with this before?