13 days late and keep getting negatives

So I didn't have a period at all last month last week on Tuesday I went to the doctor and she gave me a pregnancy test and it was nagative today I am nauseous I smell Everything and I feel so bloated i went to the gas station and almost got sick I had to have my fiance go in side and get drinks and stuff. Hot flashes and cold flashes out of no where I have never been this late other then when I was pregnant I mean I was a week late once. I just don't get it the doctor said I was not pregnant witch I new because I took a test before I went just to make sure I didn't get a surprise ya know I also have had cramping on both my left and right ovary. I am not stressed out or anything like that. Any advice ?