As noted in this article by Gizmodo Facebook has a collection of data that is kept hidden from users. This information is known to include at least all of the data in the users Facebook profile and assumed to include other data scrapped from Facebook apps on phones.
After hearing Facebook constantly talk about how they are accidentally mishandling user information I have quit social media.
Quitting social media was not easy but it was very liberating and has increased my quality of life. I highly recommend trying to quit social media even if only for a day or two the lack of constant updates makes life much better.
For more information on how bad social media is for ones health check out https://bjmendelson.com/ if you dig in far enough is books also on there for free!