Is it possible to get a dissertation done in 3 weeks??

Hi guys need some advice.
I've had anxiety throughout my last year along with being lazy I've left my dissertation to the last minute with 3 weeks to the deadline. Is it possible to do a 12000 literature based dissertation in 3 weeks and still get a 2:1?? My superviser is a harsh marker. Please be truthful! And if I can please help me with tips about how to do this

It is possible, but only if you work hard and really focus. If you put it off any longer, then you will struggle. It's not even a case of whether you'd get a 2:1, it could be the case you might not finish it for the deadline if you leave it any longer. Talk to the student support services at your university about your anxiety, they may be able to advise you on what to do. Speak to a doctor about the issue as well.

A huge problem with a project, is getting started. It can be hard to think about where to begin. The first step is researching. Think about what you want to write about, and look up relevant books / articles / videos etc. Take notes from it, be sure to make a note of what information you are getting & from there. Once you have a clear plan, you should find motivation to get started.

Make a mind map of the issues you want to discuss, and what points you want to make. Use headings & bullet points to properly set out how you want to structure your work. Once you have a good idea of what the plan is, it's the case of just pushing yourself to start writing something. If you are struggling with your introductory paragraph leave it until later.

Consider using the Pomodoro Technique as well, I know a lot of people find this helps them be more productive;
The process is simple. For every project throughout the day, you budget your time into short increments and take breaks periodically. You work for 25 minutes, then take break for five minutes.After four “pomodoros” have passed, (100 minutes of work time with 15 minutes of break time) you then take a 15-20 minute break. - http://www.lifehack.org/articles/productivity/the-pomodoro-technique-is-it-right-for-you.html

Use a study planner to dedicate sometime to doing your research, writing, and proofreading. The Student Room has a handy online tool for this that you can use - https://www.thestudentroom.co.uk/g/planner
"A good revision plan should be:
Realistic: everyone has good intentions, but be careful not to set a plan you can’t stick to. Nobody can do 12 hours of revision a day.
Detailed: a good plan breaks revision into chunks, specifies times for studying and assigns each time to a subject or topic.
Flexible: some topics are difficult and may take you longer than you planned. Don’t be afraid to adjust your plan accordingly."

You should be able to find books / guides on writing dissertations. You may find it useful to get one of them, and use it to help manage your workload.
Here's a few online guides;
http://www2.le.ac.uk/offices/ld/resources/writing/writing-resources/writing-dissertation
https://www.edugeeksclub.com/blog/How_to_Write_Your_Best_Dissertation/
http://www2.hw.ac.uk/sml/postgraduate/downloads/dissertations/dissertationguide.pdf
https://www.skillsyouneed.com/learn/dissertation-writing.html
http://library.bcu.ac.uk/learner/writingguides/1.03.htm
http://www.ed.ac.uk/files/atoms/files/english_literature_dissertation_handbook_2015_-_2016_2.pdf
https://www.ukessays.com/dissertation/examples/english-literature/
https://www.academiccoachingandwriting.org/dissertation-doctor/resources/writing-a-literature-review

Check to see if your university has a style guide, this can be useful to look at to see that you're properly formatting your work correctly. You don't want to lose marks because you've used the wrong font, referencing style etc.