Hi I'm 5 Days Late From The Date I Usually

Hi I'm 5 days late from the date I usually have my period, and for the past 3 day's I had cramping, nausea, headaches, backache and dizziness, I went to the hospital yesterday and pregnancy test was negative, I have 5 kid's and the only time I ever felt like this is when I was pregnant, Can you please tell me what else can be going on with me?