I am a hard working college student and I am studying music education. When I practice my instrument I fix everything to make the piece perfect. When every I have my final exam jury my throat locks and I am not able to play my instrument to my full abilities.

I just finished my final exam jury this week and and my throat locked agian. Driving home was hard because I could not stop crying and the locked throat was still there, lose of abitie also occurred, and I was cry for the rest of the night well hyperventilating.What causes this crying? I was diagnosed with sever aniexty back in high school, by a neurology doctor. I did take medicine for it once but when my family lost insurance because a job loss, I stopped taking it.
How can I get reed of this locked throat? Any input would help.