Why would you want to go back to a place that let you go or where you felt that you no longer wanted to remain employed??
They certainly cannot fire you!! there are procedures that needs to be followed in this regard. employers can't dismiss employees at their whim..
don't pay attention to office gossip either!! Go to work and complete your tasks and duties to the best of your ability and keep your side of the employee / employer relationship clean. should they decide to dismiss you at some point, again, there are procedures that needs to be followed, failure on their part will render them liable and you can take them to the ccma!!