The Locker(2009)

Emily is a typical 20-something with one glaring difference - for her, the line between reality and imagination has drastically begun to blur. Constant paranoia and a feeling of being followed has caused her to be institutionalized. Now she finds herself trapped between what is real, and what may be real, as her doctors tell her one thing, and her mind tells her another. With no way of knowing, she will slip in and out of truths until she can get a grasp on the world around her. You never know who is watching you.