Am I pregnant?

It's kinda weird, I'm having a episodic headache, with feeling of nausea and vomiting, I even felt tingling sensation of my breast. I check my vagina it's color purplish and my appetite is weird too, i want to eat but whenever I see food I lose my appetite which never happen to me before? It's been 3 weeks since me and my bf had unprotected sex. You think I could be pregnant? Or is it too early to say that?? Help please!!!