What's wrong with my macbook?

Hi! I have a macbook a little over a year old. It's my first mac and I love it. Yesterday though it started acting really weird. I first noticed that it was really, really hot and the fan was running. I turned it off and back on and here's what I found out:

Applications are being deleted from macbook. ITunes, IPhoto, iChat have clear question marks over icon. There are 8-10 blank spaces in the Applications folder where applications have been deleted. However, data is still there (ex. pictures still there, but no iPhoto).

Internet= Says I have internet but wont connect.

Cannot open " System Preferences" or "Internet Preferences".

If connected to home computer will connect to internet and allowed to open internet preferences but still no system preferences.

If shut down....takes a while to come back on and starts up 2-3 times.

also "Preview" is gone. Now " ColorSync Utility" opens.

Is this my hard drive dying? I'm tech challenged, so any help would be greatly appreciated.

Thanks!

 

Thanks everyone. I have everything I want backed up already.

I've just never experienced so I was hoping it pointed to a definite problem, ie. disk failure. But I guess not. So I'll run disk utility tonight.

Thanks!