Website is not mobile responsive

Hello,
I chose this theme because it is supposed to be mobile responsive and because of course I think it’s beautiful. I just published my site and it looks fantastic on a laptop, but is definitely not all the way there in regards to being mobile responsive. Specifically, it seems really slow, but most importantly, I can’t access the navigation bar…the buttons do not go anywhere!
Thanks in advance for any help (:
Kelli