Sadly, I can answer my own question now.
After a few weeks of generally feeling better most of the time, I seem to have crashed again.
Back to waking at 6am, with a horrible feeling of despair and racing thoughts. Sinus problems, tired, no motivation, no appetite.
Isn't it funny how, when you're fine, you can't imagine feeling bad...and when you're feeling bad, you can't imagine ever feeling good again?