Maybe somebody is just messing with your mind. Reminds me of the time I saw a little girl drop her coin purse on the way home from school. I figured that she'd miss the coin purse after she got home.
I picked up the coin purse and saw that she had 17 cents in it - so I added my pocket change to her purse and put it back where I found it. Watched as she went back and found the purse. I bet she wondered where the extra coins came from - but I never told her!