I worked extensively on the program yesterday (21/1/19) and when I saved and shut down it was all working properly.

When I opened the program this morning and opened preview - I am working on the final editing before upload - the menu (vertical) has turned into a hamburger button (which I hate).  This has happened before and I altered the width of the side bar to correct it but this has not worked today. 

The program has also stopped responding twice and I have had to shut it down, I have also restarted my computer after each shut down.

I have not installed any updates to the program or my computer.

Advice please?