Admin issues, I no longer have "permission" to access most of my site.

Hi there.

Forgive me ahead of time because I am quite new to WordPress, and am not overly familiar with CSS and the likes. Generally, thus far when I’ve had an issue I’ve been able to solve the problem myself, but this problem has left me completely confused.

I have not recently added any plugins or changed the CSS on the layout, or even updated my theme. I just signed on to my website yesterday, just like any other day that I would, and found that I was missing most of my admin menu. The only items showing up are ‘Dashboard’ (which is missing basically everything), ‘Jetpack’ (which I no longer have “permission to access”) and my ‘Profile’.

I looked up some troubleshooting and have tried disabling all my plugins and themes which did not help– it actually made the situation much worse because I was then faced with the blank screen of death. The only way that I could then fix the blank screen was by restoring my site, but this did not help the admin menu issue.

So, after attempting to sort the problem out and only making the whole issue worse, I’ve become weary of playing around with anything else. I am hoping someone might have some ideas on what is going on and have some tips for me. I am by no means an expert on WordPress so hopefully I do not sound too foolish here.

Please help!
My site is: http://www.stepstofollow.net