Need Help with database issue

[blind-eddie]

I received a few database error emails regarding this very subject. I went to my site to find it unreachable, meaning database errors show for every page I go to.
I have done nothing to this site in a very long time & my host say they made no changes to my server.
What would case this to happen out of the blue?
I did edit my config with edit to fix.

BTW: I have 4 vb sites and only one received this issue and config.php in others is still set to MYSQL and have no issues.

--------------- Added [DATE]1452306596[/DATE] at [TIME]1452306596[/TIME] ---------------

Looks like my host updated my php to 5.6 beta via cpanel but my sites show I am using 5.4.
I am running only vb3.8, will I have any issues using php5.6?

--------------- Added [DATE]1452308056[/DATE] at [TIME]1452308056[/TIME] ---------------

I had to switch back to 5.4, many addon site functions would not function properly.