re in the midst of one, keep caffeine and hot and spicey dishes to a total minimum or cut them out completely, get a fan for your bedroom that you can turn on and off as needed and generally, do some calming things like
yoga, stretching, meditation or anything that you find calming as being stressed will also bring them on with more strength and more often.
But, I also agree with the previous poster that getting a blood test to check out your thyroid functions is well worth it.