How big is she? Does she have a lot of pups in there? 62 days, while normal for most breeds is late for a Chi, (56 days onwards is a normal Chi gestation) most vets don't know this. If her uterus is really full, there is a possibility of primary inertia, where contractions never start. So if things don't get going soon, insist the vet sees her again. I have everything crossed for you.