Just looking at your site there, it seems it's something you will need to contact your hosting company on. You have a connection timed out, which isn't something I'm able to get past on this end. Your server is simply not responding to things at all at present. My guess would be that something is still running from your upgrade that the mysql instance isn't coping with, but your host will be able to confirm if that is the case of course.
In terms of the latter, if you wish to talk about moving to cloud, we can certainly assist you with that. You mention there also changing software. It's worth noting, no amount of software change will fix your hosting, unfortunately. That's not an effort to talk you out of it. Feel free to look around of course. Just pointing out the fact that it appears to be your hosting you are having issues with, not the software. We have many self-hosted clients who manage their own sites without issue. We do however find more and more simply don't want to manage issues they encounter, which is where our cloud comes in.
I can certainly see how that would cause an issue. Hope you manage to get the problem resolved