Nic - i've found exactly the same thing this week! i am 18w today, and was starting to have a decent and rather solid (although lopsided) pot until the last few days - i started getting some weird stretching pains, and my tummy went softer again with less movement. when it was really stretched (like painfully so) we used doppler and babies heart was loud and clear about 2 inches right of the middle of my tum. today, it was no where near that - tummy was soft, and heart beat was almost directly underneath my belly button - so it seems like the baby has moved significantly and that is why my tum feels different. the kicks are still very much on the right hand side, so we think the baby has stretched itself out - at this stage, bub's is around 5-6 inches long, so if it stretches rather than being curled in the fetal position, it's easy for it to flatten itself and put less outward pressure on your body (hope that makes sense!)

i completely understand your stress at feeling different - it's kinda scary having been through all this and then to feel "less" pregnant than you did a few days ago - but it seems to be normal. as my DH so lovingly put it to me yesterday when i was getting the stretchy pains and then nothing at all "the baby is just renovating - getting it's home more comfy - be prepared, it's gonna get worse before it gets better!" gee thanks hun... lol