Even though I try I still fail...

I have played basketball for 8 years. I thought I was a decent to great player until today... I practised so hard for 3 hours (because at our game when we were almost even my coach put in the best players and I wasn't one of them) and was doing REALLY well, swishes, layups, and drills all done perfectly. I felt on top of the world. But when I got to practice I did SO bad. I couldn't make a shot. What really made me fell bad is that this girl that is new JUST THIS YEAR did better than me. I felt like a failure. I missed shot after shot WHILE THE COACH WAS WATCHING. The only time I did good was when no one was looking. I wanted to cry but held it in until I broke down in the car, tears rolling like a waterfall. My team always thinks of me as a meh player. A few years ago I was the one who was put in when the game was close. I just feel like no matter how hard I try I will still trip up and make a fool of myself. Please don't tell me just to practise more, I have already tried that millions of times. PLEASE HELP ME.