Restore disabled process / app

I wonder if anyone can help me with this issue:-
I was familiarising myself with CMS, having a look through the list in the Process Manager, tapped on a couple of them I thought I was unlikely to use (like YouTube because my contract only gives me 100Mb per month) and hit the the Disable button thinking I could just Enable if and when I needed them again. However, they are now gone completely. I cannot find them in the processes or apps list. The icons are gone from the Apps tab. It seems more like they were uninstalled than merely disabled.

I’m using a Galaxy NoteII with Android 4.1.1