Intro & a question about feedings

Liz10/04

Hello everyone!  I''m a FTM and DS is 3 weeks old.  During my pg I spent most of my time on the December 2011 boards but figured it was time to move over here.  in the Central FL area.  DS was born at 8 lbs, 14 oz and I'm feeding him expressed breastmilk exclusively.  He usually eats 2.5-3 oz at each feeding, but the past two days he isn't interested.  He'll eat about an ounce, then go right back to sleep.  Is this normal? or should I call the pedi?