Congratulations for the soon to be mother but let's try and make sure it happens like it's supposed to.
I am going to assume you know the likely length of time she has been pregnant (Gestation time) which in dogs is usually between 58 and 65 days. Body temperature drops around 2 degree below her normal usually within 1 day of labor signs. Of course if this is the case with your female, there is a concern for complication if she has been showing signs of labor for more than one day.
To cover the signs of labor briefly, there are 3 general stages:
First stage - restless and irritable, may refuse food, may have begun nesting or preparing to give birth (whelp). The first stage may last up to a day but rarely more than that.
Second stage - Contractions begin and the dog begins to strain or may even cry or yelp every 10-15 minutes or less. This stage will usually result in the birth of the puppy beginning with the expulsion of the amniotic fluid sac (usually green) and ending with the puppy (head first, although 1/3 are born breech which is fine). The mother will usually open the sac and begin cleaning the pup after chewing off the cord. You may have to help, especially if the sac is not opened by the mother quickly or she begins to damage the puppy itself.
Third stage - rest, where some contractions occur but are mild and this is usually when the mother will pass the placenta (often times eating it before you knew it was even there). This stage may last 1 minute up to an hour before she then goes back into stage 2 which each new pup born.
From your history, it sounds like there may be some concerns so now we discuss your options.
If you know how many pups she is supposed to have (via x-ray from your vet when she was about 45 days along) then you can be better prepared to know if she has had them all or if she is having any problems along the way. If there is no x-ray, then it becomes a little more reliance on mother nature to do everything right.
The question I ask every client in your position is; "What is more important to you, the lives of the puppies or the life of the mother?"
If it is more important that the puppies be born alive with the least chance of complication even if this increases the risks that the mother could have life threatening complications, then I recommend you strongly consider a vet exam with the likelihood of a C-section ASAP. The puppies are moving, the mother is near labor if not in labor, and there is milk to be had. There is no better time for a C-section than now if your priority is those puppies and the time of gestation is with 58-60 days.
If the most important thing is that the mother live even if that means the puppies don't, then you have the option of continuing to monitor her through labor. Having her examined by a vet is still a good idea even if she is healthy and not fatigued, you can wait on the C-section unless the mother is having actual complications within the second or third stages of labor. A vet may help move things along with fluids, calcium injections and oxytocin injections to further stimulate contractions and prevent the uterus from calcium fatigue. The point is that as long as the mother is not in immediate danger, the risk of a C-section is always greater for the mother than the puppies.
If your history is absolutely accurate, the signs of labor should be quite noticeable by now or very, very soon. Check her vulva and make sure there is absolutely no evidence that a puppy is being delivered and she can't complete the delivery.
Keep us updated if you continue to have questions and can't get vet care.