I think the best thing for now is to learn how to control your breathing.

If you've never learned how to deep breathe, it's important for anybody.

Focus on your breath. Breath from the stomach. Take deep, long breaths.

Tell yourself you are calm, get into a comfortable position. Don't focus on the anxiety, but on relaxation.

This takes practice, but with time you'll get better!

A guided video like this one is great for beginning!

https://www.youtube.com/watch?v=awc8MLSpjlQ

Hope this helps.