Well there are plenty of mums who don't like their sons-in-law, which actually seems to be the main issue between you and her, OP. You did say you used to get on OK until you got pregnant and married your DH.
Unlike other posters I'm not going to rush to judgement and diagnose her with personality disorders or mental illness, certainly not on the basis of what you have said here! It wonder how much of her attitude is based on dismay at your apparent dependency.
You said:
"if I just tell them to fuck off and I never want to see them I will then have no work, no childcare and we wont be able to afford our home. I cant get a new job as no childcare and cant afford to pay it. We aren't entitled to any benefits so I really don't know what to do."
Perhaps she just wanted better for you, and would like some kind of acknowledgement that what you have wouldn't be possible without her and your dad's support. Perhaps she genuinely does feel that your DH has been poisoning your relationship.
If she is being that unreasonable, I wonder why your dad is so supportive of her? I notice everyone is saying she is toxic, but he's barely had a mention.
How is it that you and your DH are in a situation where your whole life seems to rely on your parents' goodwill? Is your DH overtly snotty with her and your dad? Why is it they are so anti your DH?
However, it may be that she has come back from holiday resolved to adjust to the disappointing reality of your ongoing dependence of you and your DH on her and your dad, and is perhaps hoping for a fresh start.
On the other hand, she might be about to tell you that it's time you stood on your own two feet and looked for a job elsewhere. Have you thought about what you would do if that were the case?
"If I cut them out I wont get to see the rest of my family as they seem to side with mum for an easy life, I just don't know what to do. I dont want to lose everyone."
So your dad and the rest of your family seem to see your mum's POV. Is that really "for an easy life" - are they all dependent on her and your dad too? Or is it that you can't see their opinions any other way? If your entire family is so "toxic", why on earth wouldn't you want to "lose everyone"? What do they say when you complain to them about your mum's attitude?
It just seems to me there's a lot more to this than meets the eye.