I stopped breast feeding my ds when she was 11 months and she never liked the taste of formula. I am now feeding her full fat cows milk but noticed that she is only doing a poo every 3-4 days and gets this really bad tummy ache. Do you think the milk is too fat for her (how much milk do they need at this stage, she get aboout 600 ml or less a day) and should I try to feed her formula from time to time (also because of the extra vitamins)?