My 6 months old has been getting skinnier and skinnier. He was born at 97 percentile, and is currently at 25... each checkup he drops by a percentile range. He only gained 100g in the last one month. Anyone knows what I can do to help him increase his weight? He is currently mixed feed- 4xBM, 1xFM. And is eating 1x purée food in the evening.