My friend and her period?????

my friend is 13 and has had her period for like 15 mths. well this mth she started and ended 1 wk and a half ago and she just started again. she wanted me to ask if this is normal. what can she do ??? what should she do?? she has bad cramps and craves stuff and is grumpy. and miserable . what caused it to come again. she is not pregnant. plz help!!