I was recently terminated from my job and was told not to disclose any details from the situation. I continue to hear about managers discussing me

The store manager and grocery manager made me sign that if I spoke about anything outside of the office I would immediately be terminated and that they cannot legally discuss it either, yet a manager who was not present within that meeting, Offered to discuss those details with another department manager and assistant manager as an intimidation tactic against the assistant manager. the assistant manager contacted me and disclosed this information. Do I have legal ground to sue the company on any grounds?