I've been practicing daily an hour for 3 or so months now. It seems like whenever I start to improve or finally grasp concepts, the next day it's completely gone.
For example, I've finally been able to get easy blowing notes and articulation that doesn't sound choppy and being able to do my major scales with relative ease, my muscle memory just knowing how to adjust to get through the notes.
Today, I went to practice, and firstly I couldn't even get a line G at piano with a split buzzing, and then after warming up with long tones tried the major scales. As I'd play the concert b flat scale, notes randomly wouldn't even come out unless I spiked my volume SEVERAL dynamics. Worse still, my muscle memory for notes basically proved to be of no use. A position and feel of a simple A on the staff didn't play an A but an E. I checked everything I was doing, my posture, embouchure, making sure I was supporting my breathing and not letting it clip. I was completely demoralized by the fact that I couldn't even play a B flat scale! Not even after assessing potential bad habits, and my chops and breathing were fine and strong.
It just seems like I have absolutely no potential with this instrument, and I've never experienced this in life before. A simple rule for me has been to practice and pay attention to technique if it isn't natural and you will improve eventually. I could play the b flat scale a few days after picking up the trumpet several years ago, and today struggled to get notes out and couldn't play the scale. What is the meaning of this?
I'm generally a fighter type of person, never to give up, but the emotional stress this instrument is causing me is beginning to be too much to bear. And I don't think I can give it up, because it's perhaps the only instrument where my lack of left hand isn't a total setback.