Stress or Preggo?

So, last month was sparse for our usual BD. Hubs started a new position at his job and he was constantly tired and slept every chance he had. Then, he got a sinus/ear infection and gave it to me (so romantic, right? Lol). Well, when the sinus infection hit, I was already 3 days late. I blamed it on being sick and sinus infection causing stress in my body and my cycle reacting to it. Well, now I am 11 days late, pretty much over the infection, except for sporadic coughing fits. I thought it would arrive by now. So... should I just buy a test now or wait or just go with Stress as an answer?