Originally Posted by hazelrunpack
I do think your dog needs to see a vet, Dimitrije. Rapid heartbeat, the appearance of anxiety, hiding, and aggression toward other dogs can be signs of pain or illness. If she checks out physically, then perhaps the vet can give you some pointers on reducing her anxiety. But I think it's good that you'll be getting her to a vet for an exam.
I agree with 100%! I would bring the dog to a vet right away , anxiety, hiding, and aggression all at once is a red flag to me . I would keep a close watch on the dog until she get the vet, and I think I OP should try not to act too scares
around the dog , she can pick up of this and that will only made her have more anxiety. I hope there is nothing really wrong with here.