What may cause blindness and/or hallucinations before sleep?

Almost every night I find myself hallucinating. If I try to stay awake they get worse. I know im not sleep deprived, I get 9+ hours every night. They have been getting worse lately, last night was one of the worst. I was looking around the room and the walls seemed to breathe, then i felt as though I were going blind. I got out my laptop but I couldnt see the letters on the screen nor the keyboard. Ive read up about hallucinations and the things that happened to me seemed similar to an LSD/Acid trip, but I haven't taken LSD/Acid nor any other drugs. I want to know what may be causing this.