IMO Lizzy is not worried about Darcy's feelings (until she runs into him in person). Her primary concern is his opinion of her. In Lizzy's mind, Darcy's finding her at Pemberley would suggest that she is throwing herself at him (one of the possibilities you suggest), but that suspicion would also include her with the impropitious behavior of her parents and younger sisters.

I think of the AD line where Lizzy voices her concern that somewhere in the world [Darcy] might think ill of [her]. This is what Lizzy wished to avoid.