[TYPO3] cannot see previews, frontend not working - no html source

[dave typo]

I have managed to login to the backend now, after finding a tx dam
bug. However, now I cannot preview the site from the backend, and the
frontend is not working either. When viewing the source code in the
frontend, nothing is present either - it is completely blank.

I used to get this error when the page was taking too long to load:

If this message does not disappear within 30 seconds, please reload.
|<strong>ERROR:</strong> No class named:
tx_ddextensionframework_stats|

however, I reinstalled the extension, DD Extension Framework, the
extension that was giving me trouble, and the error was no longer
displayed after that.

Now the pages still don't work.

any advice that could push me in the right direction would be greatly
appreciated.
thank you

-dave