Shallow breathing,tightness in chest and other body parts,fear,sweating, palpitations etc are common symptoms of anxiety.
The 1st step to take is try to calm.down.The best way is to do deep breathing particularly doing the 4-7-8 breathing method.Breathe in for 4 counts,hold for 7 counts & breathe out through mouth for 8 counts.Repeat for a few times.
Next Steps
Now either lie down/seated position make yourself aware of tightness in body.Start to relax those body parts.It may help to self talk .eg-relax neck muscles/relax back muscles etc.
Health Tips
Anxiety can feel scary but remind yourself that it is a passing phase.You have control over it.The best way is to distract from the thought that provokes anxiety and getting back to addressing it later especially under the supervision of a counselor who will help you resolve the issue from the root.