Hugs
I think we all go thru this in one way or another.
It's very frustrating and gets you down.
There was times we panicked about numbers, but in the end way more booked than we thought. And I seriously counted my list 100x times to make sure we would make our counts. It took over my life. Try not to stress just yet.
Sorry to hear your family is the hardest to deal with right now. Does your sister realize if she goes thru the States nothing is a package? she has air, resort, transfers, etc.? Maybe that would sway her. Also, maybe have a good heart to heart with her about your numbers - it's not just $200 for your sibling but more than that.
Also, when is your wedding date? The pregnancy one is hard for me - I see both sides. I see they want a child and now lol, but on the flip side I don't see that planning it around your wedding is a lot to ask. Maybe hold off a few months so she can still travel to your wedding being pregnant (ie - it's in early pregnancy not when she is ready to pop). Or wait until a month before your wedding or or or. They have options, but again I see it from both sides.
I feel for you!