Updated theme, navigation has broke.

So I updated the theme this morning and something has gone horribly wrong somewhere because now my site is all out of wack and the navigation bar is gone? (https://outbreakgaming.co.uk) Because of course I had to go change something like this without doing a backup and the last time I did was when I upgraded the wordpress version so I’m freaking out a fair bit. If anyone could help me out so I don’t lose days worth of working on my site I’d be super appreciative.

Thanks in advance,

Harry