Mitti Id forget the walk at this point, just keep her to the garden, Molly didnt go anywhere other than the garden before her pups went to their new homes, so you wont be limiting her in any way, she was also probably a bit stressed at being away from pups. Molly used to really warn our other dogs off, even if they approached the baby gate, looked like a different dog, beared her teeth the lot horrid, but her way of preserveing and protecting her new family, by week 4 she was more tollorent but shed let the dogs in but would cirlcle them away if the got to close, it was week 6 before shed let the pups play with the other adult dogs, they go very protective of their pups and also themselves, as she knows she has to stay healthy and safe as she has her pups to care for. She will be fine dont worry, once her hormones have settled she will be all loving again

You could however as she is a rescue just to be safe, ask the rescue centre for a bit more history on her if they have them and watch her interactions with her pups as they get more mobile and boistrous