Help me please

I recently had to move from my living situation where my dog was around two other dogs, and had a doggy door to go out whenever she pleases. I feel terrible but at least she’s with me. How can I help her adjust to not being around other dogs. I feel like she’s lonely all the time. I take her out all the time but she just doesn’t seem interested. I’m tempted to take her back but idk if that’s an option and I know she doesn’t eat if I’m home so I feel like that’s not any better. Please help me