Thanks for confirming! I checked out your account, and here's what I found: 1) your web server and MySQL server load are low, those look good 2) your Apache instance is behaving well at this time, and there haven't been any restarts that would indicate any recent issues. 3) you're not hitting any memory limits, and your CPU usage looks good too.
All that said, I see that both your web and MySQL server are located in our two California datacenters (you can see that in the panel at Status > Data Centers), and it looks like you're located on the East Coast. It would benefit you to request your account be moved to our newest datacenter in Virginia, which is geographically closer to you and can rule out any extra latency. If the move doesn't help, we can definitely keep digging, but it's a good place to start
Just submit a ticket requesting the move, and we'll take care of it: www.dhurl.org/dhsupport