YOU SAID:
Oh my god, I can't believe that I'm that stupid
INTO JAPANESE
なんてこった、私がそんなにバカだなんて信じられない
BACK INTO ENGLISH
I can't believe I'm so stupid
INTO JAPANESE
こんなにバカだなんて信じられない
BACK INTO ENGLISH
I can't believe I'm so stupid
That didn't even make that much sense in English.