Hmmm, will he suck on your knuckle? I've had to do that whilst in the car, at ten days old they have a growth spurt and do feed alot more, but not for over an hour. If it is a growth spurt, feed as often as he wants, and your boobs will catch up over the next 24 hours. Unfortunately they have these spurts regularly. Never doubt yourself, you have more than enough milk for him. Drink more water, eat flapjacks and porridge and make sure you rest. That way your milk will be at its best/most.
There are loads of long term BFers on here so don't think you are alone in how you are feeling xx