I've had shortness of breath before getting my arrythmia under control & it's scary, even with my oximeter telling me my O2 level was 97%. You haven't said what you have & haven't done but I have a few suggestions for you to consider.
1. Like the poster above said, get your heart checked out if you haven't already.
2. Get your name on the cancellation list at your new pulmonologist. Would a call from your primary doctor get you moved up in the appt book? Ask them & find out.
3. Relax & distract. Your brain is not your friend. Occupy it so you don't focus just on your breath.
4. CBC oil has helped me immensely when I'm really stressing. Get the oil with an eye dropper so you can deposit it right under your tongue. CBD is good too but for some reason for me, CBC really helps mental anxiety.
Oh man! I hope you can get in sooner & get this resolved. It is scary AF. 
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