I hate the new Ipad UI/Layout

Every time I open up the app on my Ipad I immediately try to hide the sidebar so I can view my messages in full, only to remember they removed the ability to hide it (why?) and I just close the app altogether because it makes me so unhappy. I've encountered missing exit buttons when viewing photos and entering search, making me close the app to get out of it. The layout before was fine and I don't understand why it's been changed to such a mess.

Just add a collapse button for the sidebar, please.