After all of your kind feedback and support, I sat down and wrote for an hour on Sunday. I timed it on my phone and set an alarm and everything.
Going back to my novel, I found it was actually in pretty good shape. I mean, don't get me wrong, it still needs work, but the skeleton is practically there. Now all it needs is a few large meals and it'll be sorted.
Now I just need to find a way to keep writing. My motivation is back at any rate, and I suppose that's half of the battle.