| Brian,
You answered a bit of your own question . . . you panicked. Don't panic when low -- just have about 15 carbs and wait 10 -15 minutes and recheck your bg. 1/3 of a Dr. Pepper alone would probably have been enough carbs to correct the low.
Did you check your bg at 12:15 before you ate the cereal? Did you match the carbs in your cereal and milk to the 3u of Novalog? It sounds like the 3u was a little much, or you were lower than you thought before eating.
__________________   Type 1 for 29 years
Pumping with MM 522 since 02/07/08
HbA1c as of 4/15/08 is 6.1 "Be still and know that I am God;..." -Psalm 46:10 | 
