Breastfeeding - HELP!!!

My baby has been breastfeeding very well since birth. However, the last couple of days he seems to get very agitated and constantly takes himself off and fusses and tries to relatch. When he relatches, he doesn't seem to be getting anything. He gets very frustrated. It's like a cycle of this during a feeding. Anyway, he is only 5 1/2 weeks old and I definitely don't want to quit breastfeeding this early. I need suggestions of what can help as I will be returning to work soon and need to be pumping to have a good supply for him also.