I'm kind of a returning player - I'm 19, but I really hurt my chops somehow around last Christmas, and it has taken me up until about a month or so ago to really get back up to my old form, and it took me up to September of this year to even be able to play well enough to get my chair back in my college jazz orchestra.
But I'm finally back to normal - I play lead in the jazz orchestra - and I've noticed something that was never really a problem before. When I play very high and hold it out, I start to feel a lot of pressure in my head and I begin to even feel dizzy. I've also heard from friends that my face turns extremely red, which it never has before. I don't feel as though I'm needing or using more effort to play the notes, I'm not pressing any more than I used to or anything, but the feelings of internal skull pressure and of (albeit very brief, normally no more than three or four seconds) light-headedness after a held-out note is a little concerning to me.
I'll note that it's only on very high notes - it almost always happens when it's the last note of a song. It does not happen when I'm playing a shout chorus - like when I need to play between high C and G at forte for an extended period of time during a song. It only happens at the very end.
For example, at the show we just played, I felt pressure and some dizziness three different times, at the end of three different songs - the notes were, in order, Bb above high C, D above double C, and double C. Each time, I felt okay after a few seconds - but those were a few seconds when I thought I was going to fall off the stage!
Is this normal? Do most trumpet players feel like that when they're pushing themselves at the top of their range? Or am I doing something wrong? And is my face turning red an indication that I'm doing something incorrectly?
Thanks for any advice y'all may have.