I have gone through an anxiety disorder a month back but now I feel completely normal. But recently, I feel like difficulty in breathing (not very severe) but I do feel, when lying or sitting. I am stressed about my exams that are going and I am on my periods too. I have noticed this feeling just 2 days before my periods started and before that i was normal. I thought this is because of my anxiety for exams or maybe because of my periods? I had painful crame too, today. Please answer.