TimeMachine icon not showing on iMac

Dear Everyone

A friends who's an IT support chap, came round to see if my Imac was working OK and he was perplexed that after I rebooted the machine a few days ago, the TimeMachine icon has disappeared from the top right hand corner on the mac desktop (is this known as the Information Bar ?). He says that if it running in the background, like the anti virus, wifi etc, the icon should be sitting alongside them as it was when he first set Time Machine up a few weeks ago.

I've lost a lot of precious photos of years because my hard drive packed up and I didn't realise that I needed to have an external hard drive. So I am doubly cautious now.

I'd so appreciate some advice here

Thank you all