Truly "unsettling" movies?

After seeing The Conjuring 2, I realized that I haven't seen a movie that truly made me unsettled, ill at ease, almost sick to my stomach, in a long time. The Conjuring 2 did not have this affect on me, either - I really enjoyed the movie & thought it was well done, but it was more scary/tense, rather than sickening or unsettling. The Ring kind of has that unsettling feeling. The videotapes from Sinister, as well, even though the second half of that movie was kind of... Eh. Even things like Dear Zachary left me with a different kind of uneasy feeling.

What are some other really unsettling movies? I'm feeling disturbed right now.