Scarlett Marie
My daughter had the very same symptoms with Enfamil. She was breastfed mostly but I also supplemented with formula. Everytime she had formula, she screamed bloody murder and contorted like her stomach was in knots. She never slept regularly and she threw up as often as she spit up (she did one or the other EVERY time she ate).
We discovered her problem to be the iron in the formula. The problem is, no formula manufacturer makes a low-iron formula anymore - even though the baby has enough iron built up in her system for the first six months of her life from being in the womb.
Drs. will argue this and tell you that iron will not make a baby sick - but they are wrong. The MOMENT I started my child on Similac low-iron, she became a different baby. I bought out the last 8 cans that was discontinued at my local grocery store and my mom wrote to Abbott, the manufacturer of Similac for any leftovers in their warehouses. My daughter is now nine 1/2 months old and can handle regular Similac better (no screaming, but not as regular b/m's) - though I still give her the low-iron primarily. At six months she started eating cereal from which she gets plenty of iron (1/2 RDA per serving - she usually eats at least two servings a day!) and I have no doubt she is not anemic.
See if you can find low-iron formula anywhere. At the very least, I would suggest changing her from Enfamil and on to a different formula. Even before we discovered the low-iron, Enfamil was the worst on my daughter's system. Otherwise, write to formula manufacturers and beg them to begin making the low-iron again because I know from my experience with the makers of Similac, my daughter and your granddaughter are not the only children they (will) have heard from. There are others, and they have received letters - but they need to know from as many as possible.
I wish you the best and hope for you and your granddaughter you are able to find a solution quickly. I know how heart-wrenching it is. I am so sorry to hear of your troubles.