I've had my periods since just before the start of year 8 and I'm in year 9 now, they had always been at the end of the month and I never got period pains, not once. But since around September I've had my periods at the start of the month and I've had loads of pains, I've even thrown up. Why is this??
a girls cycle is 28 days, not a full month so every cycle it will vary by a few days. When your young your cycle is still not regular and every period is different.