My site seems to run fine for a few hours then go down with Internal Server Errors for a few hours then run fine for a few hours then go down again back and forth all day all the time.

I'm totally at my wits end trying to figure this out.  My host says they moved me from one of their servers to another in an attempt to address the problem.  It didn't address it.

I don't know what else to do or where to even look.  Error logs just say "Premature end of script headers: index.php" and nothing else.

Help!

Site is located at http://www.saablife.com

EDIT: It's working right now, but will undoubtedly go down again soon.