pacsafeblog on "Error 500, Slow loading & drop in Sessions in Google Analytics"

Hi,

We haven't done anything with our blog and this is the first time we've experienced an issue like this for over 3 years of use.

Since last week, we've encountered the following issues:
1. We cannot post to our site. When we try to, we get an error 500

Page loads with this message:
The http://www.pacsafe.com page isn't working
http://www.pacsafe.com is currently unable to handle this request.

HTTP ERROR 500

The page URL its accessing is: http://www.pacsafe.com/blog/wp-admin/post-new.php

2. Our page loading speed is slow. Makes it look like there is no page loading because it takes long for the pages to load the content.

3. Since last Friday, in our Google Analytics data shows a drop in sessions. Which items 1+2 would be a cause of this.

April 13 we were at 3,000 sessions, suddenly we start seeing a drop on May 12 at 1200 and then May 13 400 sessions and it's staying below 400 sessions on our blog.

We checked with our IT on the server end and they cannot locate an issue. We think it is WordPress related. Can someone please help.

Thank you!