I have just logged in there, and there are a couple of items of note.
First of all, you need to address your tasks not running, as shown in the bar at the top of the page. If these are not running, then cleanup tasks are also not running.
The second item is that you have errors being repeatidly logged relating to chatbox. I would suggest disabling that, or contacting the author of a resolution to that issue.
Other than that though, it looks like you have simply outgrown the hosting you are currently using