Hello friend, thankyou for your question.
Anxiety in dogs is why many give up instead of seeking help. Congrats to you on giving this situation the benefit of the doubt.
Clearly it sounds like Seperation Anxiety. Please give your vet a call and ask for medication to help this dog. Make sure the vet understands the details of your Boxer's problem.
We have a neighbor who has 11 boxers. Six of them are puppies. We watch as the dogs have 3 acres to play in (safely fenced) and these dogs are high energy dogs and they love to be outside when the weather is ok. If anyone at your house can run with the dog,play frisbie with the dog it will help alot. They really love and need attention!
The following websites will help you understand more about this problem and how you can help.
Seperation Anxiety in Dogs
Separation Anxiety in Dogs
Canines of America Separation Anxiety and Behaviors
It's good your dog has not been hurt so far but I do caution you to remove any plants,etc.that this dog has access to.
You don't need a sick ,hurt or poisoned dog on top of the other issues!
This boxer at 10 months is a Baby!
You need to protect her from herself.
Dogs just can't explain how they feel.But they can show you and she is.
She is frustrated at being alone.
Dogs are pack animals and this dog knows that her pack (you) go away without him! (really!)
And when her pack comes back they are upset and angry ..
Also you need to begin obedience training with her as soon as you can find a class. Ask your vet for some in your area,they may know where or who gives reasonable priced classes.
Here is a website which may help you at home once you've given medication a little time to work. SoYouWanna train your dog?
If you have not had this dog spayed it would be adviseable and may help and there are benefits besides behavior. Here's a website to explain more: Spay/Neuter Behavior Benefits - VeterinaryPartner.com - a VIN company!
I hope this has helped you somewhat with a little direction so that you might get a better plan for helping this little girl become a big girl who does the right things with her family.
Giving up on her at this point would only increase her insecurities. You can change this situation with comittment,love and time.