Some of us find it really hard to say No! Sometimes it's good to take small steps to start with, until we get more confident to say a firm No! It's a way to conquer the fear head on. The Word of God says that we are more than conquerors. It may take time, but we can learn when to say No!
There is a difference between bearing others' burdens, and carrying them! Trying to fix and carry another person's load for them can prevent them from growing and learning.
Jesus said, "Come to Me, all who are weary and heavy-laden, and I will give you rest. Take My yoke upon you and learn from Me, for I am gentle and humble in heart, and you will find rest for your souls. For My yoke is easy and My burden is light."
Matthew 11:28-30.