Hi @Ctoo,
I started Letrozole 9 weeks ago and I too was very concerned about the side effects.
As others have said you just have to take it and see how you go. My advice would be to start taking it on a day when it does not matter if you do feel a bit off and best of all keep busy so you don't think about it too much. I got nausea it lasted about a week and then on an odd day for a couple of weeks after that but it was manageable and that has gone now. Hot flushes of course some worse then others, but learning to live with and manage that. I have also had sore hips which I find is not so bad on my gym days, so trying to add walks on the other days. I definitely think exercise has helped and I am seeing a exercise physiologist as I have osteopenia and want to learn how to exercise better.
All the best I hope you don't have too many problems with this next stage.