I remember these kind of sensations too - and I remember being pretty weirded out by them! DH used to watch the rolling of my tummy from across the room - if they used to freak me out then they certainly do now ha ha

Have you felt anything on your cervix yet? That was the weirdest for me and I thought bub was trying to get out - it was like a pulse deep in my bottom driving to work at the time too!

My placenta was right at the front too, and I was told the same thing, but felt alot of movement from word go, and I think it was around 25ish weeks at a scan my Ob said it had moved up and to the right, hence being able to feel heaps more.

It's an amazing experience isn't it? Enjoy