You may find it helpful to listen to your inner feelings and learn to be more honest and authentic while at the same time honoring the needs of others. A possible communication may be: I wish I could help you and do this for you, but I simply do not have the time and the energy to do it. I hope you can understand this. A person who cares about you will understand your situation and not make you feel guilty.
As psychologists we help people become more aware of their inner feelings because often people are not in touch with their feelings, especially when they grew up with the message that they have to be tough and not cry and learned to suppress feelings..
I invite you to share your experiences regarding feelings.