
I know it's not the 'modern' way of doing things, and that conception may not take place from the first mating (or even days after the first mating) but I tend to count from the first mating and then allow 2 days over if nothing has happened. THEN and only then, did I involve my vet - too much stress on pregnant mum plus the risk of infection to take her in. No way would I go for an elected C.Section. I only went down that road, plus my vets advice if mum was having strong contractions but getting nowhere in about 1 houirs - each delivery. There's no point leaving her to struggle, becoming exhausted, if she is going to need surgery. Without knowing what breed because obviously some don't deliver naturally.
She may not be very interested in food because she doesn't have much room for food now - concentrate on protein, not bulk! Thed puppies will take all they need and once you have the litter on the ground and see how many she has to cater for, then is the time to up the food intake - and probably not really until the end of the first week. Newborn puppies don't need that much milk and if she does produce lashings, she may run the risk of mastitis. Just like us, a pregnant bitch shouldn't become 'fat'.
Temperature - I never bothered too much with what that said - and for sure, while it's still fluctuating, she's not going to whelp any time soon.... it's when it goes right down, and stays down, that whelping should begin within 24 -48 hours ... by which time she'll be nesting etc too.
Some people here say yes to extra calcium. However, even with a big boned breed (I go by breeding, not feeding, for bone) I have never regularly given extra calcium (and I come from the generation who used 'Stress' ) other than the one time I did have one going into eclampsia. Provided the bitch has been fed a good quality food, before mating even, she would be fine. But again the number of puppies could need to be taken into consideration. We gave our puppies cottage cheese on weaning, so mum had some of that too

Good luck - the waiting was always the most stressful part of this experience, for me.