[Alun]

i think a more realistic and viable way to make a living as a freediver is somewhat less glamorous but perhaps far more fulfilling - and that is to become an instructor. i think it can be hard to be a financially successful freediving instructor... you need to have access to the right locations (which are not too remote/expensive) and be able to tap into a decent sized market. maybe another option would be as a commercial spearfisherman or 'shellfisherman' (if there is such a term!)?

if you become a world class diver and money comes your way then that's a great bonus, but if your ultimate goal is to become a professional full-time world class freediver then you're probably in for a bumpy ride...

regarding your condition i would seek the advice of a doctor who specialises in diving medicine.