Mobile Version Issues

I’ve been having problems with the mobile version of my website.

To start, the menu has disappeared on my homepage, so readers can’t navigate to other pages. Then, on the homepage under “Music Blog,” there’s a big gap of white space in between each post title and featured image. There’s also big gaps of space between each row of photos in the “Gallery.” I’m guessing it looks like this on all my pages, but I can’t even view them to find out.

Then, when you go to any of the posts, none of the words are visible besides the title of the article and whatever links I’ve included. You have to go to Reader View in order to read the article (it looks great in Reader View, but that’s not exactly helpful).

It’s easy to see all the issues just by visiting the mobile site. (thesoundwaveodyssey.com)

Do you think updating to the latest version of WordPress (4.9.1) and Themify Ultra will fix the issues? I’ve been worried about losing all my data during the updates, although I did successfully backup my website through my hosting site, Hostgator. I’ve irresponsibly been putting off the updates due to fear of ruining my website.

Additionally, I’ve been looking into installing some plug-ins to fix my mobile version, but once again, I’m afraid that I’ll mess things up since I’m still basically a newbie to WordPress.org. (I don’t see how plugins like AMP for WP or WordApp would fix the issues, since it’s probably all caused by me adjusting the padding, margins and other style elements multiple times on each page.)

Any suggestions are welcome! I really need some help to fix my mobile site!

The page I need help with: [log in to see the link]