Congrats on your litter! My Mia has had both 6 and 7 puppy litters! at one point just before her whelp date her tummy measured 21 inches! and gained almost 6 lbs. she went from 6lbs to almost 12lbs.
They are a lot of work just like with any other litter! Just make sure mom is eating really good (healthy) and taking her vitamins. My vet is a huge believer of this to keep mom's strength up while she is nursing her puppies.
keep in touch!
and Good luck and safe whelping!