Hi newbie hear so hope you don't mind me hopping in, it's possible the antibiotics are holding off any infection causing your ewe to much problem at the momment, have had Similar that some has hung on a few days after and got smelly, might be worth asking vet for a pessery tablet to put in her, or them to do if you rather, this will with hope clean her out a bit,
Watching she's ok in herself is important if she goes off her food etc she's getting an infection which could be serious,
Like said might pay to chat to vet again, likely he will give her something like oxytocin, what is used nornally to let milk down if they are holding it up, this also relaxs the uterus in another action and alow placenta to come out,
Hope this helped a bit,