Some of what you describe can be considered as part of the side effects panel of Cymbalta - as you have taken and had problems with it in the past, it would be a consideration.

- Fast, rapid heart rate
- anxiety
- panic attack

Having low potassium is something of concern, dependent on the value, slightly low is usually something the MD will recommend supplementing to cover; higher value deficits will need more involved treatments, and your PCP would have recommended that if necessary.

How this would couple with your current symptoms would best be dealt with by getting in touch with your PCP, to see how they would best deal with the new symptoms, especially since they resumed the Cymbalta - which you had problems with in the past.

And, MiaVita makes a good recommendation for the interim.