Glad to hear the glitch is gone and folks are able to preview themes without losing their widgets!
MelodyWluv and Acting out Mama! - it sounds like your issues are unrelated to this earlier bug, which was resolved Friday afternoon. The glitch was related to previewing themes, not switching themes. If you still need help, could you each please start separate new threads so we can help you better one-on-one? Be sure to include a link to the site in question and let us know step-by-step exactly what you did before your widgets went missing.
I'm going to close this thread since the bug's been resolved.