My dog is due her puppies any day now.?

She was shivering this morning but it stopped when I petted her, I haven't noticed her doing it again. Could she be in the early stages of labour? She wont let me take her temp and when I try to check for milk she cries. I am waiting for the vet surgery to open to take her in for a check up. I tought I would ask and see if anyone else has experinced this.