You may have had things happen in the past that erode your certainty and confidence. You need to explore how you have defined those past events and maybe consider reframing the meaning you attached to them. With a new meaning around what has happened to you, you can get free of the heavy weight of historical belief anchors.
Equally, you may be spending time worrying about the consequences of your decisions in the future. What will people think? What will people say? What if it changes everything I value about how my life is now? These questions are all a form of wasted energy, worrying about what might be is paralysing and prevents positive change. (Note: scenario planning is not worrying about the future, but rather rationally planning for possible futures and not what I am referring to in this post.)
Your focus needs to be on staying present to what is happening around you now, while taking positive next steps. When swamped by an uncertain future or simply overwhelmed by the enormity of the task ahead of you, focus on now and take a small next step. Now and Next will help you move mountains.