Yes, you are being too hard on yourself. It doesn't matter if your managers are telling you it isn't your fault. Your stuck. You have the wrong mindset. It sounds to me like your thinking ' this all my fault. I shouldn't have done that. I can't trust myself anymore. What if I mess up again.' Believe me your not the only one to have this mindset or feel this way. What you should be thinking is ' so what? I messed up I'm only human. I'll do better next time. Thank God for second chances. I can't wait to show them what I can really do next time.' Your expectations were high. Too high. You taken by surprise when something happened. A lot of times people (especially me ) imagine everything going perfectly and then life throws you something unexpected you have no idea what to do. You stand there in awe and negative thoughts and feelings fall from the sky and you involuntarily soak it up. So what do you do? You answer those phone calls proudly (even if you don't feel like it), take projects just like you would have before. Watch yourself as you succeed and fail. When you fail you'll know what not to do and you'll learn how to deal with the negative feelings and replace them positive ones.
You'll get through this. Good luck