Many individuals with ADHD have a tendency to an all or nothing way of thinking.
Often if not always ADDers think nothing they do is good enough.
Not getting started stems from being so overwhelmed with doing things perfectly.
Take some deep breathe and stop for a few minutes to regroup and visualize yourself completing the task.
Figure out what needs to be done first, second and third and manage your time appropriately.
Use timers to work and then use the timer again to pull you back on trask.
Set boundaries and work on what is the most important task.
Focus on what you have accomplished and completed, not on what you did not do.
Reframe your negative thoughts