D.J.
The baby might be allergic to the protiens in cow's milk (formula) you might try soy or continue pumping (which is the best). The child also may not be ready for solids. 6 months isn't the magical month it is just a guide when you can try solids. If the child isn't taking them her digestive tract may not be ready. Juice also shouldn't be given until the child is much older, it has as much sugar as soda and can make them sick.
Just an FYI babies aren't "lactose intollerant" lactose is in breastmilk it is the sugar in all milks. They are allergic to the proteins in cow's milk (whey).