Ditto nurse on demand. What you should know about nursing:
1. there is fore milk and hind milk. Fore milk is watery-er and that's the let-down feeling you get. The hind milk is richer and fatty-er. Make sure that you are giving your babe enough time on one breast to really get the fatty milk. They will eat 'less' but feel fuller. Also they will gain better. Also you will regulate milk production better. If you feel it's a problem, and your little one is nursing between 1 - 3 hrs., you can keep him on that same breast for at LEAST two feeds, even three if he's nursing frequently (every hour). THEN switch breasts and do the same thing.
Secondly, your supply increases as the baby sucks. When your baby eats very frequently it's a signal to your body to increase the amount of milk available. As he grows, you will notice there are days (and especially nights) that he nurses much more frequently. These are his getting ready to grow days. Then he should taper off and sleep a bit more, when he's doing his actual growing. It's really neat to see this happen
You are a wonderful mama, being concerned, but don't worry too much, just make sure he's staying on each breast a looong time. You CAN NOT overfeed an exclusively breast fed baby