Music is the biggest thing that calms my anxiety, too.I am diagnosed ADD, so minus the hyperactivity (my bro-in-law has ADHD). It really helps to get the diagnosis because then you can get access to means to manage it: vitamins, prescriptions, academic aid, financial aid, and so forth.
I can relate to the anxiety, I manage it with music: Gregorian Chant, Eastern Orthodox Chant, and etc which helps calm me when I am anxious. I also found having a squeeze ball, worry stone, or rosary beads to rub helps channel that anxiety.
I also find mechanical fidgets like Rubik's Cubes and folding cubes are calming. Don't know why.