“Shortness of breath can be caused by a number of things, according to the American Lung Association…when shortness of breath comes on quickly, it can signal emergency situations like carbon monoxide poisoning”

How to KNOW if your symptoms are due to CO? Have CO alarms on every level of your home and near every sleeping area.  If they alert to the presence of CO (4-beep pattern), immediately get out side to fresh air and call 911.

https://www.health.com/condition/infectious-diseases/coronavirus/what-does-shortness-of-breath-feel-like