I think I might be pregnant, test said negative though?

I ended a relationship last week, and I've been sick ever since then. I'm not sure if its stress thats causing me to have 24/7 lasting nausea, or pregnancy. My period is supposed to come right about now, but I don't even have cramps. I havn't been able to sleep, or eat hardly anything. I've lost 4 pounds this week alone. I just have NO appetite. The dance classes I've been taking may also be contributing to the weight loss. The pregnancy test I took yesterday said negative, but we had unprotected sex a month ago and also 2 weeks ago. Anyway does this sound like early pregnancy or breakup withdrawls? I'm gonna down some dong quai just in case. But somethings seriously wrong with my brain. I've also been crying all the time and I'm extremely sensitive, the slightest hit on my emotions makes tears pour out of my eyes.. everythings magnified.