What do I do if my dog is not eating and vomiting white stuff

You take your dog to the vet immediately.

Sorry to hear that.

She can have Kennel Cough, a notorious disease known to dogs. It's a respiratory disease that can cause lethargy and a loss of appetite. Other symptoms include eye and nasal discharge (aka mucus around the eyes and out of the nose). This can also be only contracted by other dogs.

It can also be rabies. If she''s an outside dog or has been it contact with another dog that was ill.

She could also have bilious vomiting syndrome. It occurs soon after your dog wakes up. This is caused by too much acid in the dog's stomach and is more common in dogs with digestive problems, which could also make her lethargic and will not eat because of the pain in her stomach.

Please take her to the vet because all those symptoms could be any of these or something else. It may be very Serious.

Dogs are not vehicles, there is no "book of secrets".

Animals cost money and they can get sick at times. You should have looked at your financial situation prior to getting this dog to see if you could afford its care.