Sciatica lessening but breathing problems

Listen kiddies, never get old. Since i have not been hitting class much or doing much of my cardio due to the sciatica, now my lungs have all crapped up, and I spent all last class couching up phlegm and trying not to pass out. I think I am a little better, but I have to do something that forces me to breathe on a regular basis, or I will have a real problem.