Feeling very demoralized (academic burnout)

To keep things brief: I am doing a research internship which includes writing a long form literature review as my project. I took a lot of steps in order to make sure I'm writing something every day, as before I had the habit of saving all my work until the last minute. I learned at the end of winter term that's no longer feasible, as the adrenaline would no longer kick in as my brain decided the consequences were non-existent.

I knew it'd be bad if I fell into old habits this term, so I made a strategy to compensate for my shortcomings. I found getting adequate sleep did wonders for one. But in hindsight I think it wasn't so much careful planning that made my initial dive into my project effortless, but the fact that I got satisfaction + hyperfixated on my project. It's obvious to me that I pretty much nose dived into burnout again.

I was supposed to have my draft completely finished by today. I planned to write 2 pages a day in order to reach the deadline. But even as I wrote a lot, it feels extremely incoherent. I got stuck in several places, I could only do one page before my brain gave up for the entire rest of the day. The fact that thinking costs energy on its own is so aggravating, cause that means if I'm not careful I could very well lose steam before I even reach my writing goal. My mom suggested I "push myself" further into reaching my goal, but how can I do that if I'm only halfway through and the effort it takes to focus leads into forgetting basic vocabulary? I could take a break for 2 hours, come back, and still be unable to continue. I really have no idea what I'm supposed to do.

Honestly the adrenaline I experienced before would completely negate that inability to think. I could pump out my best writing in a matter of hours due to the stress of an impending deadline, but obviously, that's not healthy. I'm trying not to beat myself up over it, but it's so hard.