I know mine was a different stage but I definitely felt a 'blobbing' sensation just before I passed both baby and then when I passed the placenta. I'm assuming it will be the same for passing the sac, you'll be able to feel when you do pass it I should think.
I think it is roughly the same in different areas, I had to go in the Friday to swallow two tablets, I think, which didn't do anything at all, didn't even get cramps from those or bleed any heavier! So when I went in the Sunday I had to have more tablets and then some inserted vaginally. Nothing happened for a few hours (think around 5 hours) so I had some more and it all happened quite quickly after that. I also had antibiotics and lots of monitoring. You should be okay to go home after the 12 hours, I think I went after 11 hours!

It is a relief to just get home and have time to yourself afterwards. Everyone was nice, staff were lovely, but I hated how the ward was next to the neonatal unit, felt so depressing! Although I would of preferred to pass naturally I think if I had been at home the time of passing baby I would of been panicking not knowing what to do so it sometimes can be nice having them there for reassurance.
So maybe they will say come in Tuesday anyway? Seems silly they aren't open on a Saturday! Try your best to get in touch over the next few days (not sure what their easter hours will be like for telephone )

Although it's horrible when you know for sure it's all over (I was in a bit of denial when baby had no heartbeat) you are also relieved in a way as it's horrible knowing your still to pass. You will feel better when it's all over I promise

Hope you get your super sticky bean soon!
xxx