I wish I never watched this film

I always thought I was pretty tolerant of scary movies and could watch anything without it really bothering me. This movie was suggested to me by netflix to rent and I watched it on blu ray by myself knowing nothing going in. I was extremely disturbed by the ending, and even months after watching it I am still disturbed by it and hate thinking about it. I'm also reminded of it by small things like turning on a lighter. Whenever I think about it I get extremely anxious, scared, depressed and disturbed again. I think there should be some kind of warning about this movie but I know something like that would be ridiculous to implement. I suppose I'm wondering if anyone can help me get over this movie. Maybe I need to talk to a shrink.