Jaffacake Sometimes children are killed with kindness. If you have always been around to bale your daughter out, protect her from the results of her own bad decisions and generally always been there to sort it out when anything goes wrong, then her definition of whether you love and care for her is defined by how much you give and do for her.
Now something has arisen where you have no alternative to saying no, she is so shocked by this she sees it as rejection and a lack of love.
I think you need to think about how to ween your daughter off seeing you as a solution to every problem; childcare, debt, housing. I am not suggesting you just turn your back on her, but just occasionally say you cannot provide childcare, cannot do this small thing, or that, until she realises that she needs to grow up, be independent and sort out her own problems.
Yes, all of us help our children when we can but we all need to know when not to help them. It have to be cruel to be kind.
As your daughter starts to take responsibility for her own life, and that of her children, she will begin to appreciate how much you have done for her.
In the meanwhile, you should point out to her that you would be unlikely to be acceptable to a lender as a guarantor anyway as your income is not sufficient and all your capital is in your house.