A while back, something weird happened to me on Facebook. And I'd like to understand and, if possible,  avoid any future occurrences.

So, here's what happened- I  was messaging a hotel who couldn't accept us. I was getting ready to look elsewhere when one of my relatives butted in and suggested an alternative solution. This relative wasn't following me but, just to be sure, I eliminated all of my followers and made it impossible for anyone to follow me.  So, as she was apparently keeping an eye on me without actually following me, I  was wondering how she did it. Can anyone shine a little light on this?

I'm getting sick of having to worry about who is reading my posts without knowing... How can I stop people tracking me?