Once very couple days around the same time in the evening I start experiencing shortness of breath. Is this something I should be real concerned about? I feel like I can only breath when I take a long deep breath, like I just finished running a marathon. Or I yawn a lot but it's not from being tired, it's to breath. Sometimes I think it's just in my head and since I'm overly thinking about it my body is reacting weirdly. Advice please!!