Thanks nix
I want to not have that job because I hate it every day and it makes me really miserable. For me the job died completely last year when an entire department was closed and let go - they were the people I mainly worked with and enjoyed working with. I was never planning to return to that job after maternity leave for lots of reasons (wrong hours, long commute, would have to be full time, doesn't pay enough for the childcare hours we would need etc).
The notice period they would have to give me is 4 months, so at 3 months pregnant that works out pretty perfectly. Financially it is much better for me to get redundancy pay and SMP, rather than to stay employed and get SMP+enhanced company maternity pay and then resign and have to pay the enhanced pay back.
And mentally I had got completely into the mindset that redundancy was coming and feeling like there was this massive light at the end of the tunnel soon and so I am also very disappointed.
Thing is, I don't do pregnant very well. And bar 5 weeks in the autumn I have been pregnant since last May (and hope to be until August!). And felt "not right" or downright awful for all of that time. Factor in all the trauma of a bereavement too and I just feel like I can't cope/can't face it all 
I don't feel strong enough to cope with constantly moving goalposts, which is probably why I've been so upset by this.
And the new job they want to slot me into involves a transfer to another department, some different work, new managers (who I know and don't really click with, very cold people)... and on my first day in my "new" job I would have to fess up to being about 16 weeks pregnant which is frankly an embarrassing position to be forced into. And I don't know if they would be sympathetic to me struggling with pregnancy. My current manager is excellent and has been very flexible about when I get in (due to sickness) and allowed me to use annual leave to mean I work 4 days a week (due to tiredness) and is forever telling me to take it easy. I value this so much, and I do think it stems in part from me being a damn good employee in the previous years and being respected by him and hence I am being cut some slack when I need it.
Gah. Sorry that is very long.
And... to add injury to insult...
I have just got piles 
Glamourous to the last this, isn't it??