HELP!!! Strange Search!?

[NBaker]

Ok...so its not that urgent but I've asked this question twice with no answers.I was looking at my activity log on Facebook when I noticed a little box I could check that said "Include Only Me activities" it has a little lock on it and I checked it and it shows if I have looked anyone up. It showed my sister and a few close friends but then it also showed many searches for this guy that I don't know. No one else has my password and I have never searched for him or know who he is. He does live in the same city as me too. What could have happened?
But why would someone go into my account to search for this guy for several months. Because after I saw the first one, I scrolled down and saw that it had been made previously for many months. I haven't posted anything that was spam or clicked on anything like that.

[Levi]

It would seem that you may have forgotten to log out on one or more occasions.

[Peter]

I would change my password if I were you, could be that someone figured it out somehow. try to have it with more complexity
http://www.passwordmeter.com/

And you can also run ant-virus in your computer to check if some trojans are on there.
PC
http://www.avira.com/en/avira-free-antivirus
MAC
http://www.avira.com/en/download/product...c-security