If you are holding on then you are trying to keep your hold on something. If you fall off of a high cliff and you are holding on then you are hanging on the edge. Letting go means plummeting to certain death. Sometimes the phrase holding on refers to a relationship that may be in trouble, and this is a relationship that you do not want to end so you hold on as long as you can.
When you start being aware of your negative thoughts, emotions and negative people that are around, you have to remove them from your life... You can't have weeds in your garden that will cover the beautiful flowers that you have ... You have to make once and for all the decision to remove them all... The weeds will grow back but it will also be less and less as you get closer to your dreams. And when you start doing so, you will finally see the path that you need to take. Book soon to be released on following your heart and the steps to take to get to your purpose.