plaintuts :
You can replace the bios battery just to be sure.
Then change the time in the bios.
But, run malwarebytes first because, most of this kinds of issues are from viruses or malware.
I ran it; it didn't show any problems. It's weird, because it's been doing this for a few days, but today it hasn't changed much (if any.) I had it off all night and all day while I was in class and came back to it a few hours ago.
Edit: After having it on for a few hours, it went ahead by three minutes, then two. It's weird. Could it be a program I have installed (IM, etc?)