Sharp pains in my abdomen, cramping,constipation, diarrhea, my period is back after one week

So Im 14, and female.

Im feeling sharp pains in my abdomin, cramping,constipation then diahrea , I feel like im going to vomit but havnt. I ended my period a week ago, but its back. And I feel super tired (never had sex so im not pregnant)

PLEASE HELP ME !!