@deathwarden,
First, how fast was your website loading before the upgrade, and what have you seen since? hard numbers would be good to have here.
Next, 36 plugins is a lot! More plugins tend to slow a WordPress site down. Do you know if all of those 36 plugins are compatible with 4.8.2? If not, you may want to upgrade them. If some are not compatible, that can be part of the problem.
Something to try, if you haven’t already, is to install the P3 Profiler plugin, at least temporarily, to run a scan to see what’s causing the slowness on the server side. If it’s WordPress itself, you should see that. If it’s your plugins, you’ll see which ones.
In addition to P3 on the server side, you should also take a look at running some tests from webpagetest.org to see the visitor side. Test it from locations where you expect your site visitors to be. This would help you figure out which requests are causing the 500 error, if you can recreate them during the tests. And as Serges mentions, you want to put Cloudflare in debug mode for this so that all of your requests go straight to your Godaddy server and not Cloudflare.
Hope it helps. Let me know.
– Jean
