Let go of the idea that the dissertation is entirely yours.
This will permit you greater acceptance of the changes and enable you to move forward with the dissertation.
Choose the filter that keeps you on the path toward completion. For every task that we do in life we have a choice whether we do it with play or not.
Try to bring play into all of your activities, including the sometimes arduous dissertation process.
“A state arising in processes that are internal and external to the individual, in which the person perceives that it is appropriate to pursue a certain course of action (or actions) directed at achieving a specified outcome (or outcomes) and in which the person chooses to pursue those outcomes with a degree of vigour and persistence” Rollinson (2002).
This research shows the expectations of motivation and how peoples needs and their expectations of working in a busy and successful environment and what their role is and how they are motivated.
Take five minutes and create a clear vision of what it is going to feel like as a graduate; imagine the things you want to do, the places you want to go, and the people with whom you want to develop relationships.
Keep that vision in mind as you move through your day and as you approach the tasks at hand. Your worth is not attached to your academic performance or your control over a research situation.
Also try to consider the changes as enhancements to your research, rather than obstacles.
Oftentimes recommendation for change further refines the dissertation. There is no area in life where change does not occur.