20% is better than 0%.
Brushing your teeth at least once every day is better than none at all.
A few hours of sleep is better than none.
A few minutes outside for fresh air is better than none.
Writing a few paragraphs of the essay today is better than procrastinating till later.
Doing something is better than nothing (of course there is exception for some cases).
Do things at a pace which makes you comfortable whilst allowing you to make progress.
You can do this!