I expect your circle will return, eventually.
I don't know about MAKING Circles, but I DID see someone who was IN Circles without even having those ancestors on their tree.
I can try to characterize the DNA Circles I've seen. Basically, none was for an ancestor closer than a great-great grandparent (born before about 1850). For my wife and I most of the DNA Circles are for our PA roots, where the families were prolific, and have been in the US since at LEAST the 1700s.
But I've had Circles on my mother's side, too, where those gt-gt grandparents were immigrants - but only when there are at least a few tested descendants out there. My father-in-law has similar roots, in a way. But for him there are relatively few tested relatives with trees, and they were not very prolific - there are no Circles for him at all.
My mother-in-law's family, on her father's side, immigrated in the early 1890s, and there are no DNA Circles for them (even though one branch has a multitude on tested people with trees).
Basically, 2/3 of my wife's DNA matches are related to her grandmother from PA, and that's where all 12 of her matches are.