Oh MrsMc I really do feel for you. Sometimes it can all just feel too much can't it.
One of the problems regarding ttc could be reading too much. I dont know about you, but I know if I read things with symptoms, I think of all the ways in which I could have that problem. This is exactly what I've done with anovulatory cycles. My OV tests said I didn't OV last month between CD10 and CD17 and, having read about lack of ovulation, I'm convinced it'll take me ages to conceive as I mustn't be ovulating at all!
I only say this because I know you are reading the book about herbal remedies and maybe that is making you think too much about all the things that can prevent conception.
I can really empathise with the work thing. I've been in the position before when I've been totally unmotivated - in the end I was made redundant (not saying at all that will happen to you!) - but it was actually a relief. I was 5 months pregnant at the time and, due to timing was not entitled to the company's maternity payments. But even if you are not employed you still get statutory maternity pay from the government if you have been a taxpayer, so dont worry about not being entitled to SMP.
Sorry I'm not being much help, but maybe you should look for another job - at least that will give you something to focus on and you'll feel like you are doing something positive.
Bodkin is right - it will all work out in the end - its just tricky keeping upbeat while it all happens.
Don't forget I am only round the corner from you (well, a couple of corners) so give me a call anytime for coffee and a chat!! I'm always up for sneaking away from work