MS List opening with a different view.......

I have numerous MS Lists. This morning several, but not all of them, started opening in Lists as below, 

As opposed to:

The tabs have also vanished form across the screen and are now in a vertical drop down men (which to be honest i quite like!). 

More importantly its now painfully slow..........

Edit: Also the logo in the tabs have changed in those affected, from the usual shaded yellow to purple icon to that of a sharepoint logo....

Is this a temporary thing? Or do I have to raise a ticket and wait for a miracle?