I'm so tired of trying to please everyone- - specifically my adult daughter, who has split from partner...?

Your adult daughter needs to start acting like an adult. She has a child to look after and it should not be your responsibility to raise that child. You shouldn't have to drive your grand-daughter to school so her mother can go on a date! The child comes first!!! Lay down the rules. If she doesn't like them, she can leave. I know it sounds tough, but you need to be strong for yourself. It really sounds as if your daughter is taking advantage of you and you are the only one who can put a stop to it.