Baby is on 6 ml zantac

BB
My baby is 5 1/2 months old and her doctor upped her zantac to 2 ml 3 times a day. Her voice is hoarse and she is waking up multiple times at night. She also doesn't nap well. Anyone else giving their baby that much zantac? Anyone have advice for me? I am terribly sleep deprived and don't even know if this is helping her :(