I see a lot people writing comments about how to improve your speaking skills (which could be something good to do but...) while ignoring the fact you're basically worried about breaking down again from the pressure.
Please take care of your basic needs and mental stability before worrying about satisfying others. If you feel you can do it, give it a shot. If not, save yourself (and the organizers) grief and bow out now.
Please be well and take care of yourself.