kinda urgent, my bubs is 3 weeks old and has ha...

kinda urgent, my bubs is 3 weeks old and has had trouble with constipation for a week and a half shes breast fed and im trying to work out whats causing it GPs seem to be useless so ive done a bit of research and im trying a gluten free diet to see if it makes a difference but i only just started the diet so its too early to tell, ive been trying to give her brown sugar water and it helps sometimes but something is still stopping her from staying regular. Does anyone have any advice for relief or what else could be causing the constipation if its not a gluten intolerance????