<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, Ive been having unpredictable menstruation for some time now. I also experience vaginal itching, and when I have my periods, they last unusually longer than before. But then I also have this problem of completely missing my period for a couple of months.  <response>: Based on your symptoms, it appears that you might be suffering from a condition known as idiopathic painful menstruation, which is also known as dysmenorrhea. 