Overloading Server

I have shared hosting for one phpbb3 and 6 WordPress sites. I’ve had these sites up for over 4 years and I have minimal expertise with php and mysql. It’s a tribute to open source companies like WordPress and PHPBB that someone like me can run sites like these.

Last week my host said that I was overloading the server and shutting it down with 2 of the wordpress sites and the phpbb3 site. They sent me a readout to demonstrate this.

As a result, those 3 websites had their database servers shut down for 3 days (the others remained active). After 3 days, the host turned on the database servers and things seemed great for a day or so.

Then the databases started bogging down and disappearing again with database errors.

What I am asking, and I don’t know if this is the appropriate place, is what can I do if it is my websites causing this overloading? I would not even know where to start hiring someone to clean things up if the problem is something in the scripts, much less would I know what to do, myself.

Right before the databases were shut off last week, I was hit with the admin password change problem that caused the new version to be issued. Otherwise, everything is as it ever was, except for recent updates and posts.

I always run the latest versions of wordpress and phpbb3.

Could this be some type of external attack? Could it be something I’ve done (such as installing or running incompatible plugins)? And how do I find out? And fix this? This situation is bad.

What do I do next?