How do you get your dog to not have anxiety and to not be afraid of everything?

I have a dog that is about 3 years old and she has some serious problems where she won’t walk outside around my neighborhood or even in my backyard and she wont even walk on certain flooring, her claws will tense up and she’ll just make a huge scene. She is afraid of every loud sound I can possibly imagine and i cant even really train or play with her because she is always scared. I don’t know if she is just scared but I am starting to think she might be depressed. Awhile back ago my vet said to get another dog and it might make her better which it didn’t. It actually makes her worse. Its just really frustrating because I’m a type of dog owner who loves to work with her dogs and play with them 24/7 but she just wont. she ends up sleeping all day long. I really need help and tips on how I can get her through this where she isn’t afraid of the floor or any loud or weird sounds and plus i want her to be able to walk in my neighborhood again and just play with me outside in my backyard. Thank you.