You'll be fine mate, I've done 3k in a week all year.
Just start writing with an idea of what you're arguing and keep making sensible paragraphs , then when you've got your basics watertight go on Google scholar and search your key points so you'll have quotes and points from whatever academic texts you need.
The research is what makes these essays long so know what you want to argue (even if it changes half way through-which it probably will) and you won't be overwhelmed
Also, please leave places for citations as you go along or else you'll cry later x