Luna

Hello, I am reaching out to you for help.
I adopted a 4-year-old plot hound from an individual this past Wednesday, and while the owner said she had some anxiety issues, they did not explain the extent of them. She is 4 years old, up to date on vaccines, and spayed. She takes treats gently and knows sit.
Let me start with the good qualities. She is a sweetheart when someone is home with her. She sleeps through the night, is house-trained, is good on the leash, likes to sniff other dogs if allowed, shows no aggression to people or pups, and seems to be good with cats.
She lived with 2 cats with the previous owner. She has lunged at my cats though, my oldest cat has been with me for 14 years and is too old to be dodging a dog that lunges at him. She also chases the feral porch kitty that I have been unsuccessful in catching so I can get her spayed and vetted. I'm working on that.
I will be completely honest with this part.
As soon as you walk out the door and get in the car to go somewhere without her, she is howling loud enough for the neighbors to hear and complain. I also am unable to take her anywhere due to if I leave her in the car, even just to get out and pump gas, she loses her mind, thrashing about, panting, and howling.
She is not destructive with her anxiety. She does hyperventilate until her tongue and gums start to turn blue and whimpers if you are with her, and howls if you are not. I left her in the house for less than two hours on Thursday for an appointment and when I came back she ran back and forth down the hallway, howling for 15 minutes. Several hours later she was still whimpering and panting and her gums were not going back to a normal pink color. I became concerned and took her to the vet who was able to squeeze her in right away. The car ride was torture for her and me. The vet prescribed her Trazadone and Gabapetine on top of the Prozac that she was already prescribed while with her previous owners. On the ride home from the vet it seemed to help or maybe she had finally tired herself out. Next, I needed to go to class last night, so I gave her a dose of her traz and gaba an hour and a half before I had to leave. Needless to say, I missed class.
The previous owners won't take her back and I can see why.
I cannot keep her. I don't want to take her to the Animal Foundation or a shelter as she won't have a fighting chance there with her severe anxiety but do have an appointment with the animal foundation to surrender if it comes to that. She needs someone home with her 24/7, with no neighbors, and is better equipped to train or manage her anxiety. If this is not an option for her then euthanasia would be the kindest thing for her at this point. I hope a rescue will take her, which is why I am writing. I am more than happy to pay if there is a fee. Please let me know if your rescue is able to help me AND her as staying in this home is not good for her either. I appreciate you taking the time to read this.
V/R
Sariah