So, your next move is...
Nothing.
Do... Nothing.
I wish I had commented sooner, because it sounded to me as if you were doing everything right, up to the point when you "pursued her" - i.e. applied undue pressure.
It never works. It almost always ends with the man being on the receiving end of "the talk".
She probably enjoyed "testing the waters" - each date for her was like reading another chapter. And the more spontaneity, fun loving progression and good vibes you threw in there, the more she wanted to follow. Nothing needed to be defined, I mean, why? You already had her out on dates, so she did in fact, give you all the information you needed.
When you pursue her, spill your guts and confess your feelings, or ask "what are we?" - You're basically giving away the ending of the story after only the third or fourth chapter. So what reason does she have to follow along now? The plot is a damp squib, and now she's stuck with someone who "wants something serious". Which is even harder to handle when you're chronically fatigued and not feeling great.
That said, I don't think you've lost her - she clearly likes you. Just back right off for the next month and let her come to you. Don't reach out to her if she hasn't messaged you first. You need to remove this sense of pressure before edging closer. She needs to know that you CAN in fact, offer her this space.
She said it herself, after all.
