WP 3.5 – Media Size?

Not sure if this is a WP Network problem or just a WP problem…

I just upgraded to WP 3.5 on my network, and most things seem okay, but now my video embeds aren’t the right size. Example:

http://eef-etc.com/friday-links-113012/

I had them set to fill the width previously, but now I don’t even have the section to change this in Settings>Media. It’s just not there anymore.

How do I get this back? The videos look stupid that small. =\