My site has slowed to a crawl

My WordPress website, http://joederouen.com/ has suddenly slowed to a crawl. I first noticed it last night as I was updating Jetpack to v3.01. I then disable Jetpack in case that was the problem, but nothing changed. I’ve optimized the tables, deactivated many of the plugins, but it’s still super slow. None of the other WP installs on my dedicated server are like this. I’ve contacted tech support for my server and they claim it’s nothing on their end.

One of the tech support people said “It would appear that the Time to first byte is for some reason very high and then once it establishes the connection the data flows quite fast.”

I’m not even sure what he means by “time to first byte.”

Any help or advice would be greatly appreciated!!

[ No bumping please. ]