I was worried I'd killed my yeast, but all seems well for now.
My diluted started was going well, bubbly, think krausen on top then after a few additions of concentrated "must" and 24 hours later, things died out.
I tossed it the primary anyway, nothing happened for 24 hours, so I bought some more yeast and was going to make another starter and take it more slowly adding concentrate. I got home with the yeast, and the primary is bubbling like crazy now!
I'm wondering if my starter being on a stir plate helped it reach it's peak faster? I'm just happy things are fermenting!
It's always easier to see after the fact, but patience is the name of the game.