So I have no /an/ related pictures, but my gf introduced the idea that my new dog may have been a service dog at one point.
Are there any ways to test for it, or to see if she just has crazy separation anxiety and needs to be a foot away from me at all times?
Why do you think she used to be a service dog, first off? Because of her separation anxiety? Then no. A trained service dog would not have that anxiety. Service dogs are extensively trained to handle stressful situations, act calm and appropriate.