you might be right that your child has the right to be here in UK as a child of a British citizen and I don't see any problem with that. The main problem I see is YOU not your child, I mean how can you get here without your husband's help and support. For sure you know that you need loads of supporting docs to get a spouse visa. Another thing is just incase you are here how can you support your child or how can you work? Child benifit alone is not enough (£90/month?

) then you are not entitled to any public fund till you have an ILR.
Of course my sympathy is with you I know its hard to be on your shoes right now:( I hope you can find a way to ease your burden right now. All the best