Welcome back - and best of luck with the G4 (One of mine's been a right bugger these last few weeks).
But don't worry about the stress - it's a great way to lose weight and start wearing all those clothes that languish at the back of your wardrobe!
Seriously though, good luck, and remember the two great maxims of life: 1) Anyone can do anything. Not necessarily well, but they CAN do it.
2) Whatever happens, they can't kill you for it (NB: generally only applies in liberal democracies without the death penalty - but the sentiment is pretty universal). And, whatever happens, set aside time for yourself and those dear to you - it's all too easy to rush ahead in a fit of vim and vigour and forget those around you. Remember, you work to live, not the other way around... Best wishes