Ok the last time I had sex was November 15 through the 20, I had just got of the depo shot the end of October. I had a little what seemed to me to be my period because it was just like the ones before but I have not had a period since the end of October. I have tender breast, stomach cramps, back pain, nausea, and headaches but they only occur when I go to bed. I have taken plenty of pregnancy tests but they all come back negative, I'm just really confused on what is going on and if I could be pregnant. I have been pregnant before and have a 2 year old but I don't remember any of these symptoms occurying with her please help