You know you can be sociable without giving them details? "Yeah, I'll be seeing family", "Got some jobs around the house that need doing", or even "nah, just taking it easy this time". It doesn't even have to be quite factual. The person asking almost certainly doesn't really care about the details, they're just trying to connect with you, so maybe have some fun with it. Hint that you have a secret identity as a superhero who fights the misuse of apostrophes or em-dashes, or that you spend all your spare time painting minatures models of slime molds.