So I've been practicing for a Jazz piece that I was moved up to 1st Trumpet on in my school and it's been going very well at first. Thing is, the next day I practice and I'm nowhere near hitting the high notes I was perfectly capable of playing yesterday and I have no idea why. It's frustrating me beyond belief and I feel like I'm about to explode with frustration, I feel like I'm regressing and I have no idea why. A high D has never given me trouble before, and now it's really tearing me down. I'm discouraged beyond belief, and I won't have another lesson until next month, any help or ideas?