Missed period.. Negative test... Losing hope!

Ok maybe you ladies can help me, my cycles are always 28 days long, AF was due last Friday, still it hasn't arrived. I have tested 5 times and each time it comes out negative. Do I just go hey I am not pregnant and move on.. Or do I force my doctor to try to give me a blood test.. I am just losing hope that this is just one messed up cycle.. If any insight that any of you ladies might have, please share... I am desperate for ideas!