At the first sign of cramps, take ibuprofen: it works better than aspirin-based tablets. Some women get prompt relief with ibuprofen; others may find they need take it for 4-5 days.
Instead of going to bed when you feel the pain, get some exercise - take a walk, ride a bicycle or do a few minutes of yoga.
Give yourself a heat treatment: a warm bath or a hot-water bottle on your lower back or your abdomen.
Some women get relief by taking B complex vitamins, vitamins C and E, zinc, calcium and magnesium. Check with your doctor.
Get a lower-back massage. Or ask a friend to apply acupressure: rub the mid back, 1in/25mm to the right of the spine, for 3-4 minutes. (You may get 3-6 hours of relief) If you're alone, press on a point two thumb widths above the wrist joint on your inner arm, in line with your middle finger.
Eat a low-fat, low-salt diet with plenty of fibre.