Late...but negative

Kendra

I am currently 5 days late for my period. I tested Friday and then was test in the ER and both negative. Is there a possibility I could still be pregnant? What could be wrong? I've been having a "pressure" (not sure how to explain it) and felt so sick to my stomach. I can't even cook raw meat without getting light headed and nauseous. Could it just be in my head?