Please help an exhausted mom

My son is 1 week old tomorrow. I am exclusively breast feeding him. My problem is that I feel he is never full. There are moments were he will sleep 2 hours at a time and about 90% of the day he is still hungry. He shows signs of hunger about 10 minutes after feeding. And I kid you not he is on my beasts for 1 hour to 1.5 hours at a time. Why isn't he full or satisfied? And how do I cut down the feeding times? Is my milk not filling enough?