why does my site title show up in navigation bar instead of the menus

I’m using a responsive theme and I noticed my first page, which I could do better next time, is showing up fine except on mobile phones. The navigation bar is showing the site title with a drop down option for the pages. It was showing fine a week ago and I’m not sure what went wrong. The website is http://www.kratomusers.com . If you look at it from your mobile device you’ll see my page title instead of the menus.