Why would a pregnant stomach shrink in 8th month?

The baby is probably dropping into the pelvis, so your bump moves down and looks smaller. If you are still feeling regular movement, and are not having any bad cramps or bleeding you and your baby are probably fine. If you are still concerned about it in the morning, do not hesitate to call your doctor in the morning, Relax, and take it easy, try not to stress! Congradulations