Period helppp!

So long story short.

Yes I’m sexually active, I’ve had my period for 5 years now and ever since I have had it I’ve always had terrible stomach pains to the point were I am in hospital because it makes me vomit it get that painful and I can’t take painkiller etc because they just don’t work for me! The doctors are saying it’s normal but I’m convinced it’s not. I get diarrhoea, vomit, insanely heavy periods as they last for about 3 weeks straight, I’m on the Jab but it hasn’t stopped my period. If anyone has been through anything similar or knows how to stop the pain please help!