Rambling post #4: Writers block.

Here I am attempting to complete my first assignment for my second year at University. It's due in on Monday and I currently have 138 out of 2,500 words written.
Back in 6th Form and even First Year I could whack out a decent essay in 1 or 2 days, this doesn't seem to be the case.
This essay was set in my PR module around 4 weeks ago, which was 2 weeks into the semester at Uni. This raised the question, "how can they expect me to write an essay on a subject I have never before studied in my life?".
As a result, I left it for a couple of weeks until I had been to a few lectures and seminars to familiarise myself with the subject. I'm a little more clued up to the subject, so why am I still sat here with only 138 words of an introduction?
I'm not usually one to stress or get upset about school or Uni work, but theres a first time for everything. This is definitely stressing me out. Big time.
Usually once I have the basic gist figured out and I have something to start on, it just flows out of me. This time i've written and re-written the essay plan at least 6 times, and it's pretty difficult to write about something when you're not even sure what you want to say.
I'm hoping i'll have an epiphany soon or a textbook will fall and open on the exact page that I need for inspiration, but right now, there is absolutely nothing working in my brain.
If anyone has any tips on writers block, it would be greatly appreciated.
Also if you made it this far, thanks for listening to me whinge.
𝕒𝕟𝕟𝕒𝕓𝕖𝕝