Why can't I find a certain user, even though I could just one day ago?

[jippii313]

I searched it up on Monday and listened to the playlists made by the user for two days, but now I can't do it anymore. It seemed like it was connected to her Facebook account.

I think this might have happened; It was pure coincidence and she simply turned it private (if that is even possible)

OR maybe she somehow saw that someone was constantly viewing her profile. I doubt this, because everyone claims that it's not available. I did not follow her account.