> Feel like I'm doing everything right but with little progress I'm not sure what else I can do for her to gain weight
I think, with respect, you really need to forget focusing quite so much on weight and hope she's going to be happy and eventually maintain her overall health. Do you intend to keep her because that too should be your bottom line. Where would she go?
We had an oh so pretty lemon/white bitch (the one I'd hoped for as dad had a lot of that colour behind him even if he was a blanket tri). Very sadly she had a slow birth and suffered as a result, oxygen starvation, leaving her very challenged - no feeling re peeing or poohing and she wasn't really coordinated when standing/moving. We kept her to 18 weeks at which point we had to make a decision about her future. I couldn't really keep her as another passenger in my ever growing pack and equally couldn't think about sending her off to a family who'd get frustrated with her short-comings, making her life potentially miserable. So we all felt enough was enough, we'd given her time. So our vet gently gave her peace.
I hope things with your wee girl will become more apparent as time goes on, so you can make a decision about what's best for her.
Sometimes breeding isn't all fun!!