How Can Low RBC Count In An Infant Be Treated?

My daughter is 3 months old. Her problems started a month back, when she had diarrhea and lost fluids from the body and got dehydrated. We admitted her in an hospital and there she given IV antibiotics as her blood work was positive for infection. She had also lost blood as her RBC count had dropped significantly. She was given blood and antibiotics and kept only on IV and probiotic supplements for 14 days. The antibiotics dose is complete. She is off the IV fluids. Her white blood count is still around 22k and stool culture is still positive for occult blood, but diminishing. Our worry is that she is now continuing to lost weight and now 2.7Kgs, her birth weight was 3.2Kgs. Allergy tests showed she was allergic to milk protein so she is now on neogain powder. We tested for metabolic disorders and that report came back negative. What should we do? We started the Neogain powder today. Earlier she was on Semilac, and then Dexolac, but her condition was not improving. Please advice