How do you stop period cramps?

I know this is way too weird to ask as a girl but I never had painful periods before ever. It started as soon as I turned 16 and it wasn't bad, just uncomfortable for like 3-4 hours on the first day.

But today out of nowhere it feels like someone tickled my lower belly so much that the whole area feels weird and painful and fatigued and my thighs are affected too and it is a different kind of pain, not the kind you get after a nice workout when you're all sore.

No one's at home and there's no painkiller and there's no heating pack or anything like that and in 5 am of this winter morning I showered in ice cold water and that probably made it worse.

I genuinely don't have the energy to get out of bed and boil some water and pack a steel bottle with that hot water and use it like a heating pack. I want to just sleep or just give up and lie down on bed and stare at the ceiling but I have my economics test tomorrow so I don't want to waste any time. If I call my mom or dad and say about this they'll freak out and leave their work behind to come back home and I don't want that. Please help.

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8 mo
The economics test was meh, could have done it better. I distracted myself by watching Sam and Colby and few stand up comedies and the pain was still going strong so I just pushed through it and sat down at my study desk after popping in a caffeine pouch and I was doing okay then I heated up some egg curry and rice for my lunch and put some butter on it and watched a Netflix series while eating that and I felt multiple times better.

Thanks for your advices, I'm actually using few of them now.
How do you stop period cramps?
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