Please help.

Had sex on the last day of my last period and after even checked the condom to make sure it didn't break or anything like that. Well it didn't and everything was fine. I was supposed to start yesterday, but didn't.  I have been stressing out a lot over other things could that be why? But here's what scares me. It's 6:54 and I couldn't sleep well I have a cough and I coughed and almost threw up. Am I just paranoid?