I hope you’re proven wrong but even if you’re not, I get the impression from this topic that you’re extremely hard working and driven and you should be proud of this. I empathise where you’re coming from, especially in situations where you feel the job is so ‘right’ for you and that, in a sense, it was meant for you and it’d be wrong for you to not have it. Any suffering we endure is there to teach us a lesson so if you feel that you fundamentally messed up, use it to make you stronger and more driven and to overcome the hurdle that your perceived error put in your way. Try to stay present. You don’t know the outcome yet so, until you know, it’s not relevant to the present moment. If you conduct an interview whilst all the while having a mental conversation with yourself that keeps repeating ‘i’m not going to get this job. I’m going to mess up this interview’, then it’s likely you will project this lack of confidence. Anyway, good luck and I hope soon you get the job you love and deserve 🙂