t-b-y-c-b:

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!