I've had unprotected sex. I've had spotting, breast tenderness, off and on nausea (little vomiting). I have been extremely fatigued. Mild headaches and light back aches. If I am pregnant, I'd have to be around 7 weeks, I haven't had sex since then I did an online calculator for curiousity sakes. I have taken HPTs but they say negative. My friend says that maybe my HcG level is still too low to be detected.