"First see a medical doctor and rule out an physical / medical problems. Once you rule that out then see a therapist. Talk it out with a professional." – this.

"First see a medical doctor and rule out an physical / medical problems. Once you rule that out then see a therapist. Talk it out with a professional." – this. Reasons: (1) If there's an organic cause, it may be symptomatic of something else; it may be amenable to medical treatment; and whether or not either of these are true, you'll know whose experiences and advice are more likely relevant to you. (2) At least part of your issue (the panic) sounds amenable to behavioral treatment, whether or not there's any other issues going on. (And if it's not – if there's an organic cause for that too – that's worth knowing.) You might have to iterate through several doctors and several therapists to find one who's effective. In parallel with this, you might want to explore whether you can work on a different schedule. I've rarely managed to do six hours of work within a 9am-5pm slot, but I can get 12-14 hours of work done a day if I get to choose the hours – align them with my energy level, take actual breaks when I flag, feel a sense of ownership and autonomy.