So I've been playing clarinet for at least two months in the school band, and I definitely wouldn't say I'm good, but I'd say I'm catching on quite well. I've been practicing, playing well, reading music well, just as a beginner should do, and we even have a concert in two days.
Anyway, I have a problem which could potentially ruin it for me at the concert. So when I play a whole sheet of music, it is really hard for me because after like fifteen measures I start to leak some air from the side of my mouth (which I got better at controlling, but it still happens sometimes. I don't think there is anything wrong with my embouchure though). I also was practicing just now and I started noticing a new problem. I was snorting at the back of my nose. It does sound weird, but it does happen to me. It is like when you yawn, and you are exhaling, noise leaks out of your nose and you get that slight "snorty" sound, or when you hear something a bit funny you just instinctively snort (for some people). But I get this when I play the clarinet. It started to happen when I was practicing just now, and now every time I start to try again it affects me and I can't keep playing with that problem. How could I fix this, and has anyone ever experienced this before, and is it common?