If it is true that the anxiety and panic are causing the depression then one would treat the anxiety and panic first. As bad as you describe it it would take meds. Benzodiazapines are very effective for anxiety and panic so if it were me I would get on those to bring the panic down to a manageable level so you would be able to go to therapy and work on core causes.

Of course this would mean seeing a therapist and a psychiatrist.

Yes people have and do overcome these things with lots of help. Currently I am free of depression and anxiety do to meds. I have also worked very hard over the years in therapy and other non med approaches to learn to live with and manage my disease. I cannot personally say I have totally overcome it. Totally overcoming it may be unrealistic. Living in a constant state of panic can be treated pretty easily. If you expect total recovery upfront you are self sabotaging. One step at a time and see what happens.