Hi!
If you have had a blood test, then you are almost certainly not pregnant. It is quite common for women to have an "off" cycle every now and again, in which they fail to ovulate. The ovaries "misfire" or fire a "dud". When this happens, no period follows since it is necessary to ovulate in order to have a period.
I often prescribe progesterone for my patients is this situation to help start their period for them. It is usually not necessary, as simply waiting for the next one is usually OK too.
If this happens only once, no big deal--if it becomes a pattern, then its a good time to give your doctor a call.
Good luck!
Dr B
have your prolactine check, if it's elevated you will have irregular periods.
I had everything check all hormones and everything else all normal and neg blood test again and still no period