WordPress site dragging

For the last month and a half to two months, I have been experiencing unusual drag on my WordPress site. It’s hosted on my server (Lunarpages).

The way it drags is what I find unusual. It’s like a bottleneck affect where nothing happens for anywhere from ten seconds to over a minute and then everything comes through as normal.

I did some troubleshooting of my own including the usual deactivating all plug-ins and reactivating them one-by-one. This had little affect overall. I also installed and activated W3 Super Cache, WP Optimize, and Query Monitor to see if it would pick up anything, and put in a generic robots.txt in case it was from bots.

The wait time isn’t consistently slow and doesn’t seem to follow any pattern. There have been times when the load time of my site was almost instant and others where it was up to 90 seconds. But it is almost always slower when I’m using the dashboard. To create one post that would normally take a minute to set up and post can take ages. Every action I perform in the dashboard results in that same wait time over again. Pressing “new post”; pressing “save draft”; clicking “add media”; waiting for images to load; typing in the image search if I need to; selecting the image and waiting for its information to load; clicking ‘post to blog’; waiting for the code to show up in the blog text. Each of these actions takes from 10-60+ seconds each. While these happen, I sometimes get the ‘Connection lost: We’re backing up this post in your browser’ error, though it always reconnects.

I have contacted my server host and they haven’t been able to find out anything in particular. I even gave them my login info so they could investigate my dashboard and again, nothing.

The only thing I can think of that would have changed around the time it started to go slow was when I got emails telling me my WordPress was updated to 4.1.4 and 4.1.5, something I didn’t do myself (it’s 4.2.2 right now). After that, I started to get constant errors of:
Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 7680 bytes) in /home/thema20/public_html/wp-admin/includes/class-wp-upgrader.php on line 1963
These occurred both on my website, meaning it wouldn’t load most of the time, and in my dashboard, preventing me from doing much.
Changes were then made to my .htaccess and ini.php files to increase the WP Server Limit, which fixed that issue. Shortly after was when I noticed everything was dragging.

Logging into my server and looking at the Resource Usage Logs, this message comes up:
“Your site has been limited within the past 24 hours
CPU resources were limited for your site
Virtual memory resources were limited for your site”
It also shows the Virtual Memory Usage as being really high, maxing out at several points over the last 24 hours.

I’m not sure if any of this might explain what the issue could be and whether it is WordPress-related or something actually with my server.

Thanks for any help!

EDIT: Apologies, my site is http://www.shuffleplay.net