Hello. I am 17 and have played trumpet for 7 years. In the last few weeks I have run into a major problem and would like some advice on how to fix it.Recently, I have been working a lot on my upper register, and not really on the lower register. Now, my low notes don't want to come out, and if and when they do, they sound weak. It feels like they are somewhat airy and the tone just isn't there at all. These problems start when I go below "C" below the staff. This is really frustrating me. I know part of the problem is from pushing the horn to my face (probably started doing it when I worked on the upper register. I know, not good).I'm not sure what else it may be. I just can't get the notes to come out correctly anymore if at all. PLEASE HELP! Actually, now thinking about it, I realize I can't even get any "buzzing" out when I try the lower notes.