You know you're tired when . . .

. . . you type your email address in backwards.

. . . you can't even spell your own name correctly.

. . . you can't hold a single train of thought--or finish a single sentence in your journal.

. . . you've read the same paragraph in your book five times without noticing it.

. . . you don't realize someone's talking to you until they say "hey, aren't you listening?"

. . . you dial the wrong number when you're calling home.

. . . you go online to check your email and can't recall why you're at the computer.

. . . just reading or hearing the word "yawn" can make you yawn.