You need a work-up for autoimmune disorders. Hypertension may simply be idiopathic (spontaneous and without relation to other disorders), the result of discomfort and pain from FM, or an indicator of another disease process. Low sodium or hyponatremia can be a symptom of an endocrine disorder or of an autoimmune issue. “Potassium rising” needs to be better defined to include what it was and what it is now, and how much it is rising. It can signal an endocrine disorder, reaction to medication, insufficient fluids, or an autoimmune disorder. Some medications can cause fluid and electrolyte imbalances also.
You need a full work up with a board certified internist (Internal medicine physician) and then a referral to Pain Management Clinic. Take care.

Have you traded in your table salt for LiteSalt. The salt substitutes are high in potassium. The rest of your symptoms are attributable to your Fibromyalgia diagnosis.