hey ,
my name is Breanne and I went through the same thing and so did my cousin. I was put into the hospital becuase of complications with the whole pregnancy thing but my cousin had the same thing happen that you are having right now. she was really stressing out and she also missed her period but took a pregnancy test and came out negative also .. she and I went to the doctor and the doctor told her that it was alright and since she had been so stressed about it that she missed a month of her period. Im not sure if this will help you or not but if you need anything let me know.