Site redirects to wp-admin/install.php

Hi all, I need some help. My site has been continually redirecting to wp-admin/install.php. It has been up and running all year, but a few months ago this problem started happening. I seem to get a few hundred visits in the hour, then it just shuts the whole site down.
I contacted my host about it and they said I have a limit of 75,000 mysql queries every hour.
I started using a cdn and cloudflare to try and help keep my site online and reduce the number of mysql queries, but nothing seems to help.
Is there a way to fix this problem? I really don’t know what else to do other than upgrade my hosting plan to a VPS or dedicated server. After a few months it’s beginning to get frustrating.
Thanks