Arrrrggghhh, aggregated device issue...suddenly missing output ports?

Hi, desperately hoping someone can advise. I really really need to get this job done, its making me cry! Was all working fine on Thursday, but on friday suddenly got missing ports message on opening project up.

I’ve been using an aggregate device set up, was working fine, hadn’t knowingly changed anything, have tried deleting it and creating a new one, but no joy. Still no sound output from Cubase. Nothing appears in the dropdown menus.

I went into Studio set Up and changed the asio driver to aggregate device and that meant that it came up as a dropdown in the audio input and outputs pane, thought that was it but no, still no sound, looking at the mixer there is no studio out signal. Sorry, am obviously doing something stupid but getting to the tired and panicky stage!