When outside, I wear a mask (Covid-19). I can breathe just fine until I start exercising. By the time I finish my 30 minute walk, I feel like I am getting no air. Once I'm in my car, I rip the mask off and I feel a rush of air. I purchased looser cotton masks thinking this would help. It does in normal use. I am not wheezing, just feel like I am fighting to suck in air. Please help.