Why does my dog suffer from sepretion anxiety?

I have a 1 year old golden retriever german shepherd mix. All was right in the world until my aunt's male chihuahua came over for a visit. She never had a problem with us leaving. Now I can't even go to the restroom without her clawing at the door and crying like im never coming back. Crying of absolute terror even when i get out of her line of sight. Also, she has become scared of my other animals. I have two guinea pigs. One of them has allergies and everytime he sneezes her ears drop back and she claws at our feet in a desperate attempt to get on the bed. I've purchased sepretion anxiety toys and increased the length of our walks. Nothing has worked and now she is keeping me up at night. I want to help her get better but I am stumped on what to do.