My daughter is 3 months old. We were giving Dexolac Premium to her and then she started spitting out. Our doctor suggested us to change the brand to Nan Pro1, however she is still spitting out lot of milk. Doctors says this is reflux. How long does the reflux stay as she has been spitting out at least 30 ml of 90 ml we give her? Is she lactose intolerant? How can we find out? Please help and suggest as we are concerned.