Took nuvigil for high fatigue from ai conditions. Was great til I developed horrific problems catching breath. Is it safe to try it again after time?

No. Not if it is clear that the Nuvigil caused the problem in the first place.
Be careful! You should talk to the prescribing physician regarding your experience before retrialing the nuvigil. Difficulty breathing could be a symptom of an allergic reaction to the medication. Also individuals with heart disease as well as individuals with mitral valve prolapse could conceivably experience difficulty breathing as a side effect to nuvigil..