What is it called when sounds start to annoy you?

Sometimes, when I’m in class, I start to become aware of every sound. Pencils writing, pens clicking, papers turning, shoes moving across the floor, everything. It makes me feel very anxious all of sudden like I’m trapped and I can’t breathe. I don’t usually get a full-on panic attack but I get pretty close.

There’s one kid in one of my classes who constantly talks and is loud and off-topic, and for whatever reason, I just get all anxious when he gets all hyped up. I don’t know why. It just freaks me out and gets my adrenaline going. I try not to say anything because 1) he never listens and 2) he has ADD so I’m pretty sure he can’t help it.

Why do these sounds and stuff get on my nerves so much? How can I help it?