That is what I believe is happening.
Can you go tomorrow and get the card reader so Rose can post some pictures please?! We're going nuts here! :~D
It's hard to describe well, but it's sounding like that to me. Mares go from looking like a beach ball to flat sided (although it's not really flat sided, just a big difference) And the bottom line, front to back goes from gently rounded to almost pointed. There may be a big milk vein in the belly, running back to the udder.