Hi, yes, it's a bit unnerving at first... it's still a little odd a year after it started happening..
On social media, girl, you have the control, so use it. Just because people are there doesn't mean that you need to allow them to pressure you.
As Kate said, make up a plausible story... that you are married, or if you clearly are out and about your town in an "unmarried" kind of way, say that you're recently divorced, living with some girlfriends, and really not ready for a relationship. Most people leave you alone if you smile and say it firmly.
Good luck
Julia