this has happened to me several times in the past few months... don't worry.. they will show up again... I had to log off of WM and log back in... unfortunately that also logs you out of CatheNation too, so you will have to log back in (and start from scratch on New Posts) but if the workouts don't show up, wait a day or so and they should be back. It happened when SNM was doing a WM update and I was pretty upset because my ENTIRE Calendar disappeared (3 months worth!) but the next day they were back.
If they are not back tomorrow, send a service request to "Contact Us" below all pages and ask for some technical assistance.