Can anyone help me deal with this pain?

Is your urine clear (aside from period related stuff)? Does it burn when you go? If not, you are probably ok there. Give it a few days unless it gets reaaaaaaaaaaaal bad. Odds are, you have what I suddenly started getting a few years ago: back cramps. They hurt like hell. Worse than any other cramps. If it continues for much longer than the period lasts, go to the doctor and get an ultrasound or other scan to rule out kidney stones and gallbladder issues.