When I last left off with Part 1, Sierra was freshly inseminated.
I remember as a child, feeling like time had physically slowed down as I awaited something exciting - Christmas, Birthdays, Vacations, etc. I can remember vibrating with excitement for days with anxious anticipation, but as I aged, that slowly waned. Now as I've gotten older, that same level of excitement is there; just for different reasons. I could barely sit on my hands long enough to await Sierra's first pregnancy check, but as days ticked by eventually the time came.
Sierra double ovulated roughly 24 hours apart, but I did my first check 10 days from the first ovulation. After what felt like searching through her uterus for hours yielding no vesicle, I hung my head and decided to try again the next day. I wasn't feeling terribly optimistic, but knew it was still very early and I anxiously awaited my second check.
Luckily, my excitement was reignited the following day, when my scan showed a small vesicle! It measured more consistent with a 10-Day size, but alas - it was there! I decided to check back in 2 days for growth, and luckily it was still there and growing at an appropriate rate despite still measuring about 1 day smaller.
Sometimes, some embryo's just measure a little smaller, but as long as they're growing it's nothing worth worrying about but in Sierra's case, given that I know she double-ovulated, I think it's most likely she actually caught off the second ovulation instead of the first.
I checked Sierra a few more times since then; once to do a final twin-check before the vesicle implanted into the uterine lining, once more to check for growth, and then a final time to check for a heartbeat before making her pregnancy public knowledge.