You must make an appointment to see your doctor.
Take your menstrual cycle chart with you and write down the symptoms that you been having so that you do not forget anything. If it helps, you can give your notes to the doctor to read.
He will likely take a blood test to check your hormone levels and send you for an ultrasound scan.
It has been known that some women have been pregnant and did not know about it, even having bleeds. It is high unlikely that you are pregnant. If you have been sexually active, you could do another pregnancy test, or wait and see what the doctor says.
You may have a condition called Cystic Fibrosis. An ultrasound scan would show any problems if there are any. If you never had an ultrasound scan, there is nothing to worry about. You lie on the bed, some KY jelly will be applied to your tummy and the radiographer will use a scanner that will show the image on to the monitor screen.
It appears that you suffer from premenstrual tension (PMT) also known as premenstrual syndrome (PMS). If you eat a healthy and well balanced diet with lots of fresh fruit and veg, cut out or cut down on junk food, processed and sugary foods (white bread, cakes, chocolate, etc) as well as fizzy drinks and alcohol, you may find that your symptoms may improve. Make sure too that you drink plenty of fluids, especially water. If you suffer from water retention, you still need to drink a lot of water and this will help.
You may also find that Evening Primrose oil, which you can purchase from the large supermarkets and from the herbal shops may also help with your premenstrual headaches and stomach cramps.
Let us know how you get on.
Best wishes.
You don't get periods when you are pregnant further more your pregnant test should be your best friend at this point.
Your period stops when your pregnant.