Is it just me? Perhaps I’ve clicked on something! Anyway I’m not keen - it looks so different. Can’t find a ‘flip’ button and the messages are in wide rows. I’ll make a cuppa and come back in a bit.
Try scrolling right down to the bottom and see if you're on the desktop or the mobile site - which ever, try clicking on that and see if it changes back to your usual format.
Could you have switched between mobile and desktop formats? Scroll to the foot of the page where you'll find, in tiny print, the option to switch from one to the other.
Um, I'm not very good with new formats - I've hardly got to grips with the old one! (Says she who over-eagerly started a duplicate thread with the limericks, whoops!). Phew, what a relief.