SPOILER ALERT!
The thing I've found myself wondering is; Considering he could see 'Frank' but hadn't met 'Frank', and yet there was a real person, who was shot in the eye, and wore that costume on Halloween... had he travelled back before, and just wasn't aware of it?
Maybe just an oddball theory about the movie, but perhaps he was so messed-up because he kept repeating the events, a la Groundhog Day, but unaware, until the final cycle when everything fell into place, and all these little clues were left for him to follow... so he would know how to finally break the cycle...
Sound crazy?