An overwhelmed mom
This little sentence sums it up right now. It is a massive period of adjustment for all of you, with or without fur and it will take time for everyone to get used to the new routine. Your dogs both know they are loved and it is obvious that they are well cared for. You still spend time with them as does your husband so they are not being neglected in any way.

And I think she sees it that way
Dogs don't analyse things like we do so she won't be thinking anything of the sort. You say she happily plays with her toys - any dog who does that is clearly quite content with her own company. I don't think you are doing your terrier any harm at all, it seems to me she has adjusted quite well.

But for some reason she wants nothing to do with me
You are judging this by human behaviour - it could just be that your doggy is sensing you are occupied with the baby right now and is just giving you a bit of space.

and......I am putting my head above the parapet on this one......dogs are animals not little people in fur coats so they don't have the kind of hang ups we do unless we project them onto them. If you are over anxious your dogs will sense it but not have a clue why - try to be a bit more relaxed around them.