filoveg, you’re not alone!
I’ve had this problem on two sites – one multisite and one single site – after upgrading to the newest version of WP. In the middle of posting an entry I get this “Connection lost” notification and then the site locks and is unaccessible for up to 10 minutes. Trying to load the front end of the site I get a “Server 500” error and instructions to contact my web administrator. If I don’t get Server 500, the page may eventually load but with a damaged appearance (most of the theme customization is gone).
After about 10 minutes the site becomes accessible again – both front and back ends – only to seize up again as soon as I try to edit a post. I’ve used Firefox and Chrome with the same result, and two different computers.
My web hotel tell me it isn’t their fault.
In both cases I’d upgraded the Yoast SEO plugin at the same time and blamed that (to the point of uninstalling Yoast), but that was NOT the problem as I have now reinstalled the latest version of Yoast (wich is what I upgraded to) and both sites are now working.
Sorry to hear you are still getting the problem over 7-10 days. My sites seem to be stable again now, in one case after three days, in the other after 48 hours. (Of course they might crash again, who knows, but just at present I’m keeping my fingers crossed and not meddling.)
I’m sorry there’s nothing constructive I can suggest, but I wanted you to know you’re not alone and wish you good luck!
