Just a quick reality check to go along with what other folks have been saying, darlin'... the baby's eating lots, you're noticed and are working to fix the problem, everything's going to turn out fine. The absolute worst case scenario here is you have to supplement with formula.

And, I won't say "don't worry" because I don't know if a new first-time parent can not worry, but remember you'll probably have a natural tendency to be more worried than you have to be, for a while.