Too early?

Nikki
Me and my bf had unprotected sex aug 10, which was the day I started my fertile week. That following Saturday morning I started getting these really bad cramps and feeling nauseous and have had them on and off since then. He is starting to have my symptoms. 
I am 2 days late and I took a test yesterday and it came back negative. Am I testing too early? Or do I need to wait a couple of more days to take another test?