I know how you feel, I hate work anxiety, it's like you sit and wait for the other shoe to drop. You feel like you have no control over the future, it is very stressful.
You are not alone. Just take it one day at a time. Try to rehearse how you will act in your meeting with the supervisor, what you want to say, how to remain calm. Ask for concrete suggestions on how to perform up to their expectations. Just try to smile and nod and make it to your leave.
How did your day go?