What is wrong with my body?!?

I am late for my period, I took an HPT on Sunday (at 13 or 14dpo) and it was negative, I had a blood test on Tuesday (15 or 16dpo) and it was negative.. but now here I am on Thursday (17 or 18dpo) and have no sign of even starting the next cycle. I called the RE's office yesterday and the nurses just said "well you should start your next cycle when you normally do, because you weren't taking any medications." I tried to explain to them that I am late and I am never late.. but they still didn't seem to "get it," so they told me to call my gyno. I called her and amazingly that office was concerned.. so now I have an appointment on Tuesday the 18th to have my cervix dilated (yet again this year) because it is possible that the scar tissue has gotten soo bad that I am completely closed. UGHHH!!