The health visitor keeps picking up on the fact my daughter doesn;t put on weight. Shes 2.5 and weighs 21lbs. Shes a good wee eater some days, then has a day or two where she picks at her food. She was 7lb 9 when born and put weight on great until she hit 8 months and had the rota virus, she lost loads of weight and never regained it. What weight should she be?