I'd have the vet run a fecal test to see if she has worms/eggs. She could and that way you know exactly what to use to treat. Say she had tapeworms, Ivermectin will take care of that, while pyrantal won't. So if they used pyrantal, she didn't get the correct type of dewormer. Hopefully they covered their bases and treated for everything, but if she had a bad infestation, it's possible not all were killed off and then they started to reproduce again and now you have a big belly.
I don't think sedation will hurt the baby if there is one, but I'd ask the vet first and see what they recommend doing.
"The greatest pleasure of a dog is that you may make a fool of yourself with
him and not only will he not scold you, but he will make a fool of himself too."