I don't think I've written very many words, per se, but I have certainly been immersed. There's been reading and note-taking and the odd epiphany and I've come up with a slightly revised first chapter. Not quite what I had in mind at the start of the weekend, but the opening has been bothering me, and when I looked at the story arc for one of the characters, I decided certain points needed to be changed/made clearer right from the beginning, before I could possibly write the next chapter. So I suspect the next week-ish will be spent making said adjustments, and in this way I re-immerse and get my groove back.
At least I have not embarked on a complete and utter re-conceptualisation and re-write of the first chapter, which is something I am prone to doing. I consider this weekend a minor victory. On to the next chapter!