R.J.
Congrats!!
First off.. nearly no one has enough milk in the beginning. For your body to start producing enough:
a) your milk has to come in
b) they have to nurse you dry over and over for your body to start producing more. SHE will create the demand by trying to eat, when there really isn't any. Our bodies adjust 99.99999% of the time if we allow it to happen. Then you'll have too much and start leaking. Then your body will be right on target. On average it takes about 4 days to a week of increased demand for your body to step it up. Supplementing with formula slows this process down TREMENDOUSLY. In certain cases it's necessary, but those cases are few and far between.
Secondly: Eating every half hour is normal for most babies when they're brand new. The process is exhausting to them and they have small tummies. It's SO common, it has a name "cluster feeding". It also helps your milk supply.
Third: Stuff yourself with food for the first few weeks (don't worry, the baby weight will come off... I lost nearly 100lbs the first year... diet later, not now), and drink yourself sloshy with water. You need the nutrients and hydration in order to produce milk
Fourth: Sleep when she sleeps. The first few weeks are a wash, as far as having a life goes. Sleep, sleep, sleep. This too shall pass. In a blink.
Fifth: As others have said... giving her cereal will screw things up big time. No lactation consultant would recommend it.
Sixth: When in doubt: your lactation consultant &/or La Leche League.
HUGS!!! AND CONGRATULATIONS!!! Now go drink something and get some sleep mama!