Dashboard extremely slow

I developed my wordpress site about two months ago and everything was working fine. As a photographer, I use the site as a photo blog with mini-galleries. About 2 weeks ago, my dashboard started working extremely slow….to the extent I couldn’t even really post anymore. When trying to do anything, half the time it times out on me and goes to a page saying “connection lost”. Every other site works fine, so I know my internet is fine. I’ve combed through other forum posts, but they’re all from at least a few years ago, so the don’t seem applicable to the 4.1 version. Here’s what I’ve done so far to try and resolve the issue:
-Disabled all plugins
-Changed the theme
-Deleted all photos
-Deleted all posts

Nothing has worked, it is still so slow! I’m so frustrated! Would appreciate any help….