GIRLS ONLY / missed work because of period?

Have you been to the GP concerning this, asking for advice as to what you could do to help?
If it's really bad, I'd say it is a valid reason

I have before. I got someone to cover my shift for me so it wasn't a huge issue. If you're in and painkillers aren't helping, don't go in. See your doctor about getting some more powerful painkillers or perhaps going on the pill.

Yeah I’m on the pill have been for around 5 years now, my shift is today I’ve missed the cut off point to get someone to cover but I was thinking about talking to my manager i don’t know

I would speak to them, yes. I can't say how seriously they'll take you - if your manager is female then there's more of a chance she'll be able to relate but a lot of the time men really don't understand just how awful period cramps can be. No harm is trying, though. As long as it's not an excuse you use all the time, they should be okay.

Well I know what type of pain you mean. Not the ones that just hurt, but the ones that get you lying on the floor in an awkward position for like 2 hours. It happens to me a few times a year, but not to anyone else I know. Sometimes I have these pains and I just sit there in class with a pen in my hand just gulping down water shifting position on my seat like I'm some reckless kid. And yes, teachers do look at me strangely, but I try not to make it obvs. Just try to work and do as much as you can and if you can't then it's fine.