Call your vet and do the spay. Before day 19 any ‘pups’ aren’t even attached to the uterine wall, pregnancy can’t be detected. Do they spay, do it soon and she will be at no increased risk.
She can still be spayed and aborted later, but these come with increased risks and costs.Call your vet. Spay her asap, ideally as soon as she’s off heat to be easiest on her.
The ‘pups’ are, at this point, clumps of cells that aren’t really living things any more than a single cell is. Do the spay when the appointment comes up, it’s no different and will be vastly better for her than trying to carry the pups to term. Pugs have enough health issues without trying to carry pups that large.