Sue, 

I'd hold fire for a while before you do anything drastic. If your pc has a memory problem, it may just be that the citations and media are not being displayed properly and are really still there.

A simple check might be to look at the size of your last saved gedcom file and compare it to the size of the zipped file in your earlier backups. If the size is not substantially smaller, it may indicate a display problem.

Other users are much more experienced with this sort of stuff than I am, and they may well offer better help, but I advise waiting for a while until they can assist.

Hope it all turns out to be something simple and that no harm is done!