Getting Fox Terrier Advice
First, don't wait until the problem escalates into something serious. If you have purchased a puppy from a reputable breeder, then they are the first phone call that you make. Tell them what is going on and ask for suggestions and help. If you choose a good breeder, they will be able to explain what is happening and ways to work with your dog to clear up the problems. A good breeder will have gone over all the aspects of owning a Fox Terrier with you before buying your puppy.
If you did not get your Fox Terrier from a responsible breeder then you have a bigger challenge. Commercial and "backyard" breeders are primarily interested making money. There is little knowledge of the breed or of its needs. They take little care in providing puppies suited to a particular breed, and in many cases the family finds out too late that this cute little "fuzz ball" is actually not a lap dog but instead a ball of energy who needs lots of exercise, as is the case with Fox Terriers.
Education is the key to everything. Knowing what the Fox Terrier temperament is like and about the dog's needs can make a big difference.
There is a lot of information on this site that should help you. Please take the time to read it. If there is an American Fox Terrier Rescue group anywhere near you, call them. They may be able to help you. Often just knowing why a dog does something, can make a difference.
Most problems can be worked out if caught quickly and treated accordingly. Like raising a child, having a Fox Terrier in your life takes time and patience and commitment. Throughout much of a Fox Terrier's life, the dog is high energy and needs time for exercise. If this is not possible in your schedule, then both you and the dog might be happier if she is in another home.
If you are having problems with your Fox Terrier, call right away and see if an American Fox Terrier Rescue person can help you. Rescue workers are always happy to advise on possible solutions so that your dog can stay with you. If that isn't the best choice then realize that the rescue may not have room right at that time, so let them know as far ahead of time as possible if you need to place your dog.