City - It seems like this is causing you a lot of worry and turmoil. It's a very important decision, that is completely personal to you. Of course it is the financially sensible option, to take a break.
But it all depends on how important this new job is for you in the grand scheme of things?? What would you do if you conceived this month? (Be over the moon. Of course.)But when baby is born, will you want (be able) to do the same job? That is relevant I think?
Will it really affect your reputation if you were to fall pregnant straight away? Does that matter? I am not suggesting I know the answers, I am just throwing out questions, really. I hope I don't sound flippant.
Personally, there is no way I could stop trying, but then our situation is very different. I think that losing 1.5 months salary is not the worst thing, you could put a little extra away each month to cover it, perhaps?
Also, if you were to conceive next month, you will be heavily pregnant at that critical time in your new role... something to think about perhaps??
I have just waffled on here... probably no help at all. I hope you come to a decision that you feel happy with, though, I suspect it's not as easy as that.
When is your appointment again??