So I've been playing for about 4 years and I'm currently a junior and 1st chair at my schools symphonic band and top jazz. Anyway, I'm about to die because about 5 months ago I happened to switch mouthpicecs from a YAMAHA 11B4 to a E9.1 * shew 1.5 by J. marcinkiewicz. And stating from this morning jazz band I was unable to play anything above a medium E. and then I would be able to hit really high note like the E about that. But nothing inbetween. I 1st thought it was because I was tired but it would be the same after 5 hours. I'm really about to cry because I have to perform tomaro and I also have a concert coming up in a week. I would appriciate any help ASAP thanks!!! should I switch back to my old one? do you think its just a stamina problem?