Yoast WordPress SEO settings menu gone

I’ve noticed that my WordPress SEO plugin (by Yoast) settings menu in the sidebar has disappeared. The only way I can access the settings is by going to the plugins page, clicking on settings and cycling through the introduction tour until I get to the right page.

Does anyone know why it has disappeared and how I can get it back?

Also, I don’t know if this is related, my Editor under the Appearance menu has disappeared as well. These two probems may suggest that I have a problem with user access depending on role but I am the only user and I have not changed any settings from the time when these two options in the side-menus were available.

Thanks