Sorry to hear this, I had this for years in early adulthood, it can be horribly debilitating.
Finding a GP who understood it helped because some folks I saw were clueless. I was put on all sorts of meds and had all sorts of investigations unnecessarily. Was sceptical, but one GP told me it was all in my head and suggested CBT, which did actually help, but possibly not for the reasons they thought. Mindfulness practice also had a positive impact for me
From my experience each person almost has to find out what worked for them though, so definitely worth exploring, researching, asking
Colofac was the only medication that helped me but I know there are a few others these days. Colpermin worked for someone I know, but not me. I used to carry lots of extra strong mints everywhere and drink mint tea a lot - both helped. Ginger tea seemed to help but I wasn't so sure if it really reduced the pain / cramps or just the associated nausea
Diet changed didn't seem to make much difference (was pretty good anyhow) but exercise did. Not super vigorous gym stuff but long quick paced walks in the country / park. Mine eventually faded over several years, no idea why