He's fine. My daughter was like this and I found it to be a blessing then and now. If he's not waking up in the middle of the night, hungry, then he is satisfied and fine. Believe me, he isn't laying in his crib thinking that he should just ignore those hunger pangs and sleep through them. His metabolism may not be as fast as someone else's baby and that's fine.
Are you breastfeeding him? Because if you are, it sounds like YOU'RE eating right in order to provide him with adequate nutrition to get through the night. Even if you're not breastfeeding, you're doing something right. The human body - at any age - experiences hunger as a chemical reaction to a depletion in nutrients. Our metabolism, activity and diet are involved in that process. So he eats... how is his activity during the day when he's awake?
Also, the Old Mothers always said that they grow when they sleep (and hiccup). Other, important, chemical processes occur when we sleep too. So your 7 week old son is fine and doing what he's supposed to do.
As long as his bowels are regular, his eating stays consistent (and even increases as he grows), and he stays clean, healthy and happy - you're golden.