forgot to winterize and it went to 21 last night

I think I really screwed up

Probably,but maybe not.Do you have a walmart near by?Is so get some rv antifreeze there.Jumper cables to your battery if it's dead or low charged.You can make a adapter hose to pump from jugs to lines.If you need to clean out the tank you can do that in the spring.Run your furnace and pump and dump anti freeze in the drain.Not hard to do and can save many dollars in damage.If you don't know how to do these things,Google is your friend. Good luck.