Hi OP - firstly I completely sympathise.
I know only too well the pressures of a dissertation and nice and quiet , comfortable space to study and headroom are essential.
It sounds like you’re being afforded none of the above - this sucks.
There are some very unhelpful replies here essentially downplaying your need to study properly- I found when I was studying for my a levels my home environment and my parents attitude to higher education were not conducive to a good study environment. Hence me leaving school and getting a job.
Environment is key!
Do you have any friends or close family that could loan you a spare room for a day? You could drive over..
It’s a same libraries are closed that would be ideal.
I’d go with ( if you have to stay at home and cannot go back to uni accom) some earplugs, or some noise cancelling headphones?
I love a big desk to study and I sympathise you haven’t got access: maybe a table top fold out desk ( as already suggested).
Not sure what space you have available.
I like the work through the night suggestion too: completely reverse your sleep pattern. Work till like 3 -5 am if poss and sleep all day. Make your own food and snacks then if mum complains tell her it’s the only way to get the work done.
It’s your dissertation, and don’t give up your right to have a proper study space or study time. Dont settle! Make your study time yours, and no one else’s. It may be your mum just doesn’t Understand how much pressure you’re under and Time consuming it can be. I’ve been there!
All the best- keep plugging away. Work through the night and review the next day. Take regular breaks and try to send to someone to proof read 