2007 Ford Focus - radio stays on when ignition turned off - how to fix?

I've had the car for 2 years with no problems with the stereo. But today I got in (key in my purse) and the stereo was on. This is not usual and I'm afraid the battery will be drained if I forget to turn it off manually.

How do I return the stereo to the original status of turning off when the ignition is turned off?

There is also a little circle icon that appears to the left of the time on the LCD display. I'm pretty sure this wasn't there before.

I've looked online and in my owner's manual and can find nothing pertinent. Please help!

Thank you,
A.