It may not be enough, but it is the best you can do.
Your feeling of guilt may stem from your unwillingness to tell yourself that you have fulfilled your responsibility as a daughter. This may also be a result of that your mother has been guilt-tripping you since you were young because that is something a controlling person would do. You have been conditioned to feel guilty and inadequate no matter how much you had done.
So, to feel better, if that's what you want, tell yourself you have done more than enough. Your responsibilities to yourself and your family come first.