Hey Hi. Whatever she is having is quite common at her age. Please don’t stress out. First make her understand that she is your beautiful girl with a bit oversensitive body.  Keep stress away from her around that time as much as possible; keep her busy with physical activities; give her a easily digestible diet with a lot of fluids around that time and may be you can think of giving her Vitamin B capsules for a month or 2
If you still feel she has disruptive symptoms affecting her routine activities, please check with your gynecologist
All the best to you

She may have hormonal issues and/or she may be anaemic. Most girls have PMS symptoms. Make her keep a calendar to be aware when they are due. Make her aware that her periods are a proud part of being a woman and to accept them…

Take her to an gynaecologist- she may have fibrosis… she does not need to suffer this much. Making her comfortable is not the issue – getting to the bottom of the issue is critical otherwise she may develop other issues like anaemia.