From what I remember from my reading of the 6th book, an overdose on Felix Felicis (Luck Potion) makes someone TOO confident, almost to the point of going head first through EVERYTHING, but it DOESN'T KILL THEM (directly at least).
I could be wrong of course but that's what I recall...
Anyway the series rocks, except from the often typos and slight grammatical errors, but nothing too serious.
I would seriously suggest getting at least a couple of people taking your chapters through beta before you publish them.
Other than that everything's cool.
Expect to see more written ASAP!!! ;) ;)