A couple of things that might help:

• Use music to help calm yourself
• Carry some things in your bag or backpack that comfort you...objects that have a special meaning to you, words that are comforting, a sketch pad, phone apps/pictures...anything that can distract and comfort.
• On a college campus, look for calming places to relax before going to class. I used to spend time in the library or outside on a bench.

It isn't easy. I have the same issue with work and coping with anxiety.