I read somewhere today that babies snooze for 14 hrs a day in the womb so maybe they are sleeping? Mine started about 16 weeks but it was very intermittent but last few days its been everyday but not all the time, he has 10 mins of wriggling then nothing for an hour or 2 then he'll go for 20 mins hiccuping, rolling or kicking, each time he has a kicking session he's in a different position either up by my belly button (they are the strongest kicks) or down right in my groin which are much lighter and harder to feel. So when its early days of kicking you might not always notice cos they are smaller and can still fit in places you might not feel, the placenta can cushion a lot of the blows. I read somewhere mw's are only concerned about lack of movement after 24 weeks I think so up until then its normal to go a few days without feeling them.
Ps gorgeous scan pic of the placenta pillow!!! I'd love a 4d scan oh won't let me!!!