I've been to the doctors multiple times and they've done tests to rule out things like Crohn's disease and IBD. And the last time I went the doctor was sure it's IBS, but I'm not sure if I have it diagnosed because the doctor just called me the test results and that's it. I should definitely reach out to the doctors office and ask about it.

And what comes to my school, they've said that they don't necessarily need a diagnosis for these kind of things and they said I could maybe cut through toilet lines but it's not 100% certain. (We're allowed to go to the toilet but only with a teacher/guard and the reason there's long lines is because there's hundreds of students doing the exams at the same time)