Embarassing moment

I've had a few doozies of embarassing moments in my life, this one wasn't so bad, but I got a good laugh out of it.
The other day I went to Caribou Coffee for a little coffee treat while getting a few hours alone to myself. Its been a really busy week with lots of details to manage...to say the least, I was distracted and sleep-deprived. It went like this:

Amy: Walks up, squints while reading the drink option menu. Decides on a "coffee cooler", much like a Frappacino. Approaches cashier and ask "Can you make that drink iced???"

Cashier: (looking confused) "...but, it IS iced."

Amy: (feeling stupid)..."OH! I mean can you make it DECAF?"

Cashier: "Oh, sure. No problem. That will be $3.48"

Amy: Hands cashier $3.00

Cashier: "Uh...Do you have $0.50?"

Amy: (confidently) "Nope." (thinking I gave cashier $4.00)
A few seconds later (feeling even more stupid)...
"Oh my gosh. I thought, uh...here's another $1.00"

Amy: A few seconds later..."OH! Hey, I have $0.02 so I can get $0.50 back...."

Cashier: (confused) "Um...then your change will be $0.54..."

Amy: (now wanting to crawl in a hole)
"...You'll have to excuse me, I'm really out of it. AND, Please don't tell anyone you've talked to me!!!!"

The cashier was very sweet and a very good sport. She was probably thinking "Geesh, she should have gone for the caffeine!!!"