I have the same problem. Last week I added WooCommerce and YITH (catalog mode). All seemed fine. Today, I log in and I no longer see (in the sidebar) ‘Appearance’ (with theme and such), Plugins, WooCommerce, User Admin, Theme admin (maybe more, but those I remember using before and they are all gone). I fear the site/account was hacked and I’m no longer admin, only user. Is that possible???