I seem to be having an odd problem recently.
Usually warming up helped me but I could still play decently without it in some respects (I always warmed up despite this; don't freak out). Lately, I can't get above a top-line F, have to use excessive air, and I feel that there is much more deliberation, if you will, in the note coming out (if it can at all).
Some days after warming up, I overcome this and play normally. Some days, even after warming up I seem to be stuck with the problem and play just terribly.
I realize the internet's not the best place to ask this, but my teacher's still in PA from ITG.
My warmup consists of: chromatics, scales, arpeggios, clarke 2 slurred, tongued, double tongued. Note that this is my warm up...I do exercises on top of this such as lip slurs and Stamp, but that's usually later.