Preggo?

I'm usually super regular with my periods, but im almost 2 weeks late. We have been trying and I've taken a few tests over the last week. Last one was this past Friday but they've all been negative.

Is it possible to keep getting negative tests but be pregnant? Or maybe it's just stress or something. Nothing has changed with my diet or lifestyle. My boobs have been a little bigger than usual and I've been extra tired. I know the only sure way to know is testing but just wanted some input. Thanks ladies!