I celebrated by handing out some Doctor Who Valentines to the rest of my Cult of Skaro (aka my three little sibs):
They were very excited.
If you haven't seen this wonderful set of Valentines before, they're available for free download
here. (Or you can give a small donation to the artist)
Other than that, I bought myself lunch and spent the rest of Single Awareness Day with the family. It was good fun.
For a hermit :P
ETA: This
tumblr. I literally can't stop laughing.