My 3 1/2 yr old daughter refuses to go poo on the potty. she did really good for 4 days in a row going, but now its been 2 months and still wont go. ?

Power struggle: Most 3 year olds "get" the concept of stooling, but some haven't realized at that age that they want to. Sometimes it's the classic power struggle of them pushing back against parental expectations. In your daughter's case, by 3 1/2, it may be a pure power struggle. There may have also been a painful stool, and she became scared to go, or she's scared of the potty itself.