So- I open it up, it bounces for an age and then it just stops and says it's not responding.
I've updated it, signed in and out of CC. Deleted all cache files and preferences files in my library as another post recommended.
I have a report to do for my dissertation at university and can't have it acting up right now. I already don't have enough time!
Try resetting your InDesign preferences:
Close and relaunch InDesign and IMMEDIATELY hold down Ctrl + Alt + Shift (Windows) or Cmd + Ctrl + Opt + Shift (Mac), and respond in the affirmative to the dialog asking if you really want to replace the preferences. You must be extremely fast on the keyboard (if you don’t see the confirmation prompt, you were too slow!)
(And make sure you have incremental back-ups, held externally, of your dissertation!)