My dog is throwing up bile & blood, won't eat, & is losing weight?

I'd say your best option is to take her to a different vet and get a second opinion. Write all this down so you don't forget to tell them anything. Once you have told them ALL these details, including previous treatments, how you kept her under watch, food hasn't changed etc the vet might be able to give you a better idea. Its the same with people doctors - one might pick up something another missed. A second opinion is always a good idea