I see people in the corner of my eyes and when I look they're gone. Websites say it's DEMONS?!?

Well Dear, It could be a mental disorder and you may need treatment. If you are noticing any other symptons such as paranoia or voices in your head, etc then you should seek treatment. Now, if you believe that this is the paranormal and you don't want this to continue, then you should say, "In Jesus Name I command you to leave!" Any Demonic spirit won't hang around or visit if You say this. Now, try not to give in to these shadows or visions. Just let it go. Try not to watch the paranormal shows on tv or study or investigate or ask about them. Lastly, it could possibly be your eyes or like I said before a mind condition and this is very real. I applaud your courage and take a deep breath. I feel like you are going to put an end to this. Take Care!