HAD PERIOD 10/28 - HORRIBLE CRAMPING TODAY - HELP!!

To make a long story short, I had an ectopic in April and lost my left tube. My period is pretty regular being on the 28th of each month. I had it for about 4 days starting the 28th of October. Today I woke up to horrible, horrible cramping and I cannot get it to go away. It has no came with any spotting. I have a call into the Dr but haven't received a call back. Am freaked out and scared, please help!!