Hey man, take it easy! Keep the temper at bay! If you don't get it, don't worry! I had a wall that I struggled with a few days ago, I did it twice, then after that, I couldn't seem to get up it for the life of me. I just tried it and tried it, I didn't succeed, but you know what, it gives you better technique, experience, and more exercise.
But tonight I upped something that was 6" higher than that one! LOL You have good days, and you have bad days. I find eating a lot before riding helps too. There are a lot of little things...like foot positioning, shoes, and even socks, that can throw you off!
Just keep at it man, try to find where your weaknesses are, and fix it. And remember, if you can't get it, don't get pissed! You'll get it another day.