I dried myself on a random curtain.
Why did you dry yourself with a curtain rather than using a towel?
All my towels were in the laundry.
That curtain is probably dirty you shouldn't be drying yourself with it. Make sure that you always have a towel ready to dry yourself with.
My curtains are clean. They get washed every other month.
Curtains are not always clean enough though. Towels are made for drying you off, you can't be going through curtains to get dry. Curtains are probably full of dust by the time you wash them again.