I Am Not Perfect And I Hate It!

I have a serious problem of wanting to be perfect at everything I do! This will definetely become a problem when I start my acting class at the end of January! UGH! Why am I such a perfectionist? Why do I work so hard at making it right? Why do I get frustrated when I can't get it the first time around? Yesterday in my voice lesson, when I couldn't sing, (OK I'm exagaratting) but I didn't sing my best! I got so upset with myself, and went home and practiced, practiced, practiced, practiced until my vocal chords was on the floor, and I could barely sing anymore. What???? They say practice makes perfect? Right? Then at the gym today, I couldn't get an excercise my traininer was teaching! I couldn't do it? My heart raced, my mind raced, and couldn 't grasp at the idea that it wasn't happening? I kept trying, and my trainer encouraged me by saying" in time, I will be able to do it and, that I just need to work on my core more". But I was not happy with it, and it ate at me the whole day! UGH! I hate this perfectionist side, wish me luck, and I hope I can breathe through it!