On ssri constantly convinced i'm dying doctor at a loss panic attacks lasting daily

Tell your doctor: Without knowing more, this is my first advice. There is a light at the end of the tunnel so to speak. The first step has been taken (you are on a medication). You might need a different dose, a different medication or a combination of interventions and therapies. The next step is to make sure the prescribing physician is aware that you are still in distress.