I am sorry that it has taken a while for someone to answer your question.
Your pet may be showing signs of low blood calcium levels, and it is reccomended that you have her seen as soon as reasonably possible by a Veterinarian.
These signs may indicate several possible problems.
The most common cause is Ecclampsia, also known as "milk fever." This is due to a rapid drop in blood calcium levels due to the high demands for calcium by the mammary glands. Calcium is required for muscle contractions and normal body functions and decreased levels may lead to vomiting, diarrhea, weakness, lack of appetite, panting, and tremors. Once these signs are noted, oral calcium supplements do not usually work and prompt veterinary care is needed. Bloodwork will be needed to determine her blood calcium levels, and usually IV calcium gluconate is needed to get her back into balance. This may also mean that the pups will have to be weaned early, to decrease the demands on the mother.
Other possibilities include uterine infections or retained placentas (x-rays and bloodwork may be necessary). I would worry more about her calcium levels first - find out if this is the problem FIRST and then check the others if her levels are normal. This can be a progressive situation and may lead to further problems, weaknesses, etc. if left untreated.
Pets with ecclampsia still try to function normally. SOME will eat and drink sometimes...and it is instinct to continue to feed her puppies. Her body puts the calcium into the milk and takes it away from the rest of the organs, so she will continue to produce milk and feed the puppies. Panting, diarrhea, and increased water intake are possible signs of this problem - in a new mother, this needs to be ruled out (or in) as soon as feasibly possible.
When taking her to your veterinarian for an evaluation, make sure to take the puppies with her.
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(Please be aware that I work nights, and follow-up questions asked in the daytime may experience a delay in waiting for an answer, or may be answered by another expert.)