I have my period and have a kayaking field trip tomorrow. what should i do to relieve any menstrual pain?

Call your gyn: But otc Motrin or advil should help, but u need to see your gyn after u get back for an evaluation as you can be put on different meds like low bc pills or Lysteda and script meds for the cramping like anaprox (naproxen) ds, etc, no reason to suffer each month or at your age if u don't want kids i would offer u office tubal sterilization and then endometrial ablation, I do both, so no preg or periods or meds.