Multi-tasking
People who experience stress are often able to process multiple amounts of information in their heads or have two or three different tasks on the go at once. Inevitably this becomes a programmed reaction and difficult to stop. More than this it feels normal to be able to do this.
Consequently, changing this pattern to a more simple work process doesn't always occur to the multi-tasker. Part of the reason for holding on to all those jobs is that this type of person is often not good at delegating. Learn that others do things differently not less well simply because it is different to the way it is usually done.
Be strict about identifying the task you want to get done first and focus on this. Practise delegating more often. Don't become like the woman who had burned out because she couldn't stop an d had too many things to do. She reported that even when she visited the loo she would dust every surface she could reach while sitting there!!