Lost my voice the day before the wedding!

Let your voice rest as much as possible and drink hot tea with lemon.

Rest your voice. Don’t try to talk. Gargle warm salt water and drink some hot tea. Hopefully if you rest your voice from now until your vows, you’ll be able to get the words out.

Hot tea with honey and no talking! Definitely don't whisper because that actually puts more strain on your vocal chords. There is a tea called throat coat that I've used with honey before for sore throats. It doesn't taste the best (unless you like licorice) but it definitely helps.

I used to drink straight lemon juice when I was a cheerleader.
Now I drink whiskey.

HONEY.

Lots of honey. Do not talk unless you absolutely have to. Put more honey in your hot tea.

Don't whisper or strain your voice, use text-to-speech on your phone until nearly go time tomorrow.

Do you know how to support your voice with your diaphragm (the way actors do)? When you get ready tomorrow, do some gentle vocal warm ups (humming, deep breathing, etc.).