I've heard about all kinds of bizarre side-effects but never stomach cramps after weed

Hangover type symptoms are usually from dehydration and your body trying to rid itself of toxins.
Are you buying it from some random individual or from a licensed producer and/or Alberta cannabis store? Ever since they legalized weed in Canada everyone's growing it and you really have no idea what you're getting. Maybe they're treating it with some chemicals during growing or curing. Some pesticides are
extremely toxic even in tiny amounts (which is why their usage guidelines and timelines are super strict). It could even be some mold on improperly cured or stored weed that you're not seeing or smelling. Mold is nothing to take lightly: almost all molds produce poisonous mycotoxins that could cause stomach cramps
Order some different strains of weed from the Alberta Cannabis Store where it's from reputable licensed producers that know what they're doing. Try a few mellow Indica strains to start
