To the doctor, Joelogan I say - yep, train hard for the ratings and see where that gets you in a couple of years, using your current salary and fulfilment to see you through that phase, then decide whether to take a risk and leave doctoring to fly professionally. You will in your former profession always have a job and revenue stream to come back to if flying needs to be put down for a while or completely but never give doctoring up right now in this climate.
Treat it as an early career break, a sabbatical if you like, to pursue a long held dream. Brilliant, but keep the current job otherwise as someone has said check yourself in for psychiatric assessment.
To the police contingent who have contributed - I have had the privilege of doing the career break thing from the police and flying professionally and totally recommend it, but again, keep the current job don't chop that pension in. (Try Africa if you really have to do a career break, great place to fly,gaining loads of quality experience)
Now in a few years a new government may start to tax the commutation as they already did with some very senior people in the Met (different contract to you and me though which is why they could I think) and when they do tax it that might be the time to do some calculations and see if it makes no difference to leave at that point, preferably once 25 years done.
In the meantime do the CPL/IR training and see if in a few years when the economy has recovered a bit you can land a part time flying job (try compressed hours, 4 days a week at 10 hrs per day) to get the best of both worlds. Or retire after 30 yrs like someone I know who now flies Learjets for a living, having been a multi IR instructor for several years. Nice, and rather obscene to talk about in front of other mere mortals given our level of job security which is a bit of a rarity nowadays.
The police lot can PM me if you want more info on being paid during career breaks etc - I resigned and had to come back in but nowadays I think you don't have to leave...
Good luck everyone.