3 weeks late.

I am 3 weeks and 3 days late for AF. All negative HPTs and I just had a blood test done and It was negative as well. I have lower back pain, nausea vomiting, my nipples are tingly and sensitive to touch, I have mild cramping occasionally, Very and I mean very very sensitive, little things make me cry, mY husband told me that my chicken was dry and I got So upset I cried! I just want to know what's going on with me, people say stress but everything is going so good and I am not worried about anything. So Is it possible I'm still pregnant even after all the negative tests?