It is common to have irregular periods the first year that you start your period, but that doesn’t explain your “extreme pelvic pain” which isn’t normal. You should definitely make an appointment with your health care provider as soon as possible to discuss your pain. Some reasons for pelvic pain can be caused from an infection in your pelvic area, appendicitis, severe constipation, endometriosis, etc. however, only a doctor can make a diagnosis.