So i just finished an oral examination the other day and I feel completely humiliated. I answered some questions correctly but I had massive brain-farts and I couldn't keep a coherent thought alive for more than a few seconds. I felt completely overwhelmed with the situation and I feel as though my whole education slipped out from under me. To give an example I was asked if potentials could arise from non-conservative forces, and though in any normal situation I would have said something brilliant about path dependency I answered 'yes, they can' like a blundering idiot. . . This has haunted me for almost 36 consecutive hours and I cannot sleep because of it. I keep wondering if the physics department is going to tell me to get lost or if I will lose my research assistantship. Any advice on this matter would be brilliant. Am I overreacting?