we recently adopted a puppy from a shelter and all seemed well. but today when walking her she began to bend the joint over her paws almost as if she were walking on her tippy toes. after doing that for awhile she fell on her face. we helped her up and took her home. she continued to do this as she walked around inside our home. is this something we should be concerned about? or is she just going through a phase where she isn't adjusted to her legs yet? she does have rather long legs for being only 3 1/2 months old. any advice as to what to do to make this stop?