Stupified

Did someone cast a spell on me that I was unaware of? It can't be.
Still puzzling over our most recent Gryffindor homework, a cryptogram.

e fm dfu, qfet kfxxg ey vjd rjesb, whxg yjd akxjhnk
kem qj qkfa kb akjhnka kb menka faafsu qyfpb ey
f mjmbya "qkby pjxjrb ea! mfqabx gjhqbvw!
qpfa qyfpb.

Hmmmm.