Answer: sillyme

AnswerCrossword Clue
SILLYME[Headslap]
SILLYME"I should've known better"
SILLYME"What a fool I am!"
SILLYMEWords before "And here I thought ..."
SILLYMEVerbal alternative to a head slap
SILLYME"Gosh, what was I thinking?!"
SILLYME"What was I thinking?"