It can take a good year or so for you to get into a predictable pattern for your period. Remember that the length of your cycle is counted from the FIRST day of 1 period to the FIRST day of the next. In terms of your period pain, it is quite common to have severe period pain as an adolescent. See your pharmacist to start with for anti -inflammatory medication such as Naprosyn or ibuprofen. Start taking it at the first sign of your period pain and take it regularly for as long as the pain is there. If this isn't enough to settle your pain, see your GP.