Thank you all SO much for your advice and well wishes!! I LOOOOVE the idea of doing pilates or yoga instead of cardio (at least til i can get my breathing normal again). Hopefully i will kick this cough soon and get back on that treadmill....THANK YOU!!
When in doubt, trust your body. I find that the increased circulation from light exercise is good for fighting nasal congestion when all I have is a head cold (no working out with a fever!), but definitely don't overdo it.