Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am very sorry to hear about your girl. I understand that this is her first litter, and they may be overstressing her body.
Pregnancy and producing milk for a litter of puppies is a lot of work for any dog and can be very taxing on their bodies. Some dogs develop hypocalcemia (low blood calcium) due to the demands of producing milk for a litter of puppies. These dogs will have panting, restlessness, drooling, vomiting, tremors, weakness, may have a change in personality due to the effects of low blood calcium on the brain as well as stiffness in their gait or weakness. It can progress to seizures and if not treated, death.
If this is what is going on with her this is a true medical emergency and she needs to be seen by a veterinarian immediately. They will check her blood calcium levels and start intravenous calcium immediately. If this is her diagnosis the puppies will need to be bottle fed and weaned now, she cannot feed them any more or she will become hypocalcemic again.
Other possibilities for her symptoms are an infection, either mastitis or a post-whelping uterine infection.
I recommend that you check her mammary chain and look for any signs of redness, firm swelling or pain. If those are present then mastitis is possible.
Does she have any yellow, or foul smelling vaginal discharge? If so a post-whelping uterine infection is possible.
Treatment of an infection can be antibiotics, but as sick as she is she may need to be on intravenous fluids and injectable antibiotics and in many cases the pups will need to be weaned.
Whatever is going on with your girl she does not sound normal, and the conditions I listed above are not conditions that can be treated at home, she needs emergency veterinary care. Whatever you try to give her orally won't be enough to replace what she needs and may cause her to vomit which will cause dehydration. I understand not wanting to stress her at all because she isn't naturally friendly with strangers, but I think that her situation warrants an emergency visit.
Best of luck with your girl, please let me know if you have any further questions