Hi OP, sorry to hear that they're putting you through this sort of thing whilst being pregnant.
If this is the sort of establishment I think it is then I'm not surprised at all I'm afraid. They only look at figures and treat you as a number.
Is there someone that you trust in there that you could talk to about it and maybe get a second look at the decision?
If not, then yes it is very unlikely that you would get another job whilst being pregnant, especially if you're past 1st trimester. (I know because I became unemployed right before finding out I am pregnant and I haven't been able to find a job)
If that's the case for you, then I would recommend signing on until you can claim for Maternity Allowance. That's what I had to do and have just swapped over to MA now. It's not ideal but it's something, and you should qualify for MA as you have been working up until this point.
Look on www.gov.uk for info on both JSA and MA.
I also know how it feels to be shat on at work, it's not a nice feeling at all, but things will work out. You have to concentrate on looking after your little one >.<
xx