For every patient i see, who wants 100% guarantee for the treatment given to him, I ask him the simple question - "if he can give me a guarantee that I may not break one of my bones of my body today!" He has no answer!!!
Similarly in life, as Rahul dravid says in the max new york ad, you never know when life can run you out! So you gotta be prepared for everything in life.
All these fields are bound to be saturated in the near future, similar to PLAB . But then if god shuts one door for us doesn't he open a few more(similar to Australia )?!
One very positive thing i see these days is that India is progressing leaps and bounds and wonder, if there was no corruption in India, it would have easily surpassed maybe even US by now, but thanks to our whole corrupt system(well US should thank them for still being on No.1 spot.). But indeed I see a very positive picture of India in the near future, a picture of developed India, a real India Shining!
And also you see there is less of brain drain as more and more foreign companies are coming into India and investing and more and more people getting highly paid jobs in it.
Enough of philosophical thinking, in short be ambitious and reach for your goals.
So stop worrying, identify your goals and work hard to achieve them.