Doctor has currently given me a fluconazole prescription as we are trying to treat daily constant diarrhea weight loss and occasional fevers at night. extremely worried about side effects (heart, i have low bp(not medicated). havent taken it still?

Side effects are rare with fluconazole, and the severe ones you mention are extremely rare. Whether it will help your symptoms is a separate issue -- candida overgrowth is the only thing it might treat, and even when candida is present in the intestines it isn't necessarily the cause of symptoms like yours. However, it certainly won't hurt anything to give it a try.