quote "I started gaining serious ground every few weeks. As of about two or three weeks ago, I was consistently playing double C’s and higher as part of my daily warm-up, and my playable range was flirting with double G’s (two G’s above the staff). I even hit a triple Bb once (three Bb’s above the staff). It wasn’t loud, but it was there. "end quote
I'm not a high note specialist, but I can't imagine why anyone would want to consistently play double C's as part of a warmup. It sounds to me as though you've strained and/or exhausted part or all of your embouchure. It's always interesting to me when people have these problems and somebody tells them they need to get back to basics and that helps them. This should send up a big red flag -- somewhere you've gotten away from the fundamental principles of playing and screwed yourself up. This high note technique and regiment sound to me like they're screwing you up.