Teen unwell during every period

[Sunnydaize]

For the past year my DD15 gets unwell the day before every period begins and lasts until it finishes.
She will have flu like symptoms, headaches, swollen tonsils, high temperature, and at least once she will vomit. She doesn’t suffer with period pains anymore and they’re not particularly heavy.
Does anyone know if this is linked with anything I should be concerned about, such as endo or similar? I have pcos but I have never experienced this myself.
tia

Ask your GP for a referral

Dd used to have these symptoms ( but not swollen tonsils) along with cramps and flooding. She tried a couple of contraceptive pills and settled on the implant.
Every symptom has since disappeared so we assumed they were related.