You didn't fail! The company failed you. The last thing you want to do now is dwell because it will only make you feel worse. The best way to get over this is think positively. Dismiss your employers judgements and get out there and find yourself a more enjoyable job where they like you for who you are and treat you fairly. In a couple of months when you have a new job you could be looking back on this as a good thing because it helped you find a better suited job. I find it helps if you think like this, please give it a go! And all the best in the future!