Book with a main character who must uncover the truth about a mysterious situation they’re in

I’m looking for a book in which the main character suspects that people are trying to hide a certain truth from them OR finds themself in a confusing/mysterious situation that’s centered on them — leading them to seek the truth after being in the dark for a while, or for their whole life.

Not really looking for fantasy or historical fiction (though they’re not deal-breakers), but fine with romance, horror, thriller, YA, literary fiction, “women’s fiction,” or even memoir and true crime.

Examples: *A Day Like This* by Kelley McNeil, *Before I Go to Sleep* by S.J. Watson

by imisspuddingpops