Yeah, typically when I play these games, particularly Black Plague and Amnesia, I feel mentally unstable afterwards. About 2 years ago when I played Penumbra everything felt.. dark. But in a good way. It's like when your in a theater and assume it's dark/raining outside even though it's not.
Penumbra: Overture has a welcoming dark presence that lingered in my subconscious for a few months. Black Plague was different. I felt the bad kind of fear.. everywhere.
Amnesia has me pretty freaked out too right now, especially since I played it for almost 2 days strait now. And now it's even worse since I'm talking about it. But.. In my experience watching a few hours of tv can fix me up in no time.