So scared, sick and upset

I hate my period because my period means unbearable pain and though I have  high pain tolerance I still end up in so much pain I can't breathe for pain. I have to wear adult sized diapers and pads. I have to wear countless layers of underwear. I feel like a big wedge of nausea is stuck in my throat. I feel sick and I feel dizzy and I don't WANT my period anymore because it messes everything up and means I have to take time off from university. This isn't a medial reason and I'm always told if only I ate more or if only I was stronger I would be able to overcome this, I'm told to brave it and go to uni even though I sometimes pass out and end up in the ER. Every single report and medical test result has come back clear stating I have no problem and this is normal but it does not feel normal. It is embarrassing and painful and I don't know what to do anymore. I can't exercise because that seems to worsen it. I feel like I'm just full of pain and blood waiting to explode from pain. My parents don't accept any form of birth control or anything similar to that because our culture does not accept that at all so that is out of the question. I actually do not know what to do to handle this because I have guests over who would never, ever understand what was happening and I can't be in pain but I can sense I'm starting today because I can feel that sickly wedge of nausea in my throat.