Something that helped me with the anxiety and racing thoughts when I was waiting for the GAL’s decision was to visualize things going in my favor. Maybe try to envision your mediation going how you want it to go, if your afraid your w will monster visualize how you will calmly respond and steer it where you want etc.
Im sorry about what she is doing to d w/grades. Your doing a good job being a rock for your kids keep it up!