You can start the weaning process as early as three to four weeks but you need to be sure and feed the pups a balanced diet to supplement the loss of their mother's milk. I have attached a link to a wikihow document that walks you through the process. Best of luck with you new puppies!

http://www.wikihow.com/Wean-Puppies

I agree with Molly... I think you should be okay. I would add that you should get your puppies to the vet and have them checked out also just to be safe.