Here is a simple rule of thumb to live by. If you get any online product for free, then you are the product. Eventually all big companies need reliable data to justify their existence. FB masks their one true purpose with a social media cover, Google might use one of the many at their disposal. In the end, it will be unfair to say that their services are completely irrelevant. An average person can have a symbiotic relationship with such companies provided he/ she has taken adequate precautions & restrain themselves from infinite scrolling.
The web is open and the alternates are out there. Do a bit of exploring. Maybe you will land on something larger, get to do more meaningful work and build a really worthy online profile to truly understand the worry behind such data leaks.
The issue is not about what info Facebook (or Google for that matter) has about you. Rather this fiasco is all about questioning their integrity when it comes to managing this data and ensuring they are the smartest in the room & not some unknown third-party app maker who can extrapolate or steal your intimate online details. If you want to worry about something, then let it not be for the data you shared so far, but rather how very little you can control such corporates when it comes to whom they share info about you and how much!
In a digital age, those who know what to do with data and control it will rule it all! But do not the big shots mislead you with the illusion of control! In the end, it is you alone who control your data. Try not to be too naive and just be vary of what you say or where you post.