Speaking from experience, fam... There is no "taking a break".
When I dropped my last LP in June of 05', I put in a big push. I toured, did guest spots, got some press, made a buzz... Like you, I moved that first thousand in a matter of a month or two... But here I am, a year and a half later, and I've moved just over 3300 units of that LP.
I decided to take some time, to be with my newborn son and my wife. I turned down some shows I should've done, and I lost a lot of my buzz. The quality of the music has kept me moving units over the time, but I find myself at this time, trying to rebuild what I had in the summer of 05'. Had I attacked in fall of 05, and carried that buzz on through to 06 strong, I easily could've moved double what I've done by now...
I'm currently working on a new project, which I hope to get signed off of. I'll be shopping it to labels, and trying to utilize that previous buzz to get me some notoriety within the underground/indie scene. I'm praying it works...
I had a good reason to fall back when I did... My son was more than worth losing my buzz over... But I think if I had put my mind to it, I could've maintained my status and pushed it further without sacrificing my family like I thought I would. Live and learn I guess...