No period for 7 months, negative hpt and blood test

I am going through the same thing as some of you ladies my last period was in April and have took several hpt in which was negative. I have had no symptoms at one time I was sleeping alot and feeling sick but I have been to dr took blood test and pt both said no. I have to go to the dr soon and I'm going to ask why is that I hadn't had a period in all this time. I watch that show I ddnt know that I was preg and when i see that I be thinking that that could be me. I have mild cramping like a period is coming but never do. I don't know what else to do.