Rusty is very eager to please, sometimes anxious, and never leaves my side. I was told he’s a GSD…

Rusty is very eager to please, sometimes anxious, and never leaves my side. I was told he’s a GSD lab mix, but he’s a lot smaller than both of those breeds. I think there’s some GSD, but not show bred since it must have carried liver, mixed with something else/ the street dogs of the area. He’s was gift from my great uncle, who lives in a very rural area where dogs kinda run wild. He’s pretty lazy.