Drs don't have you start monitoring movement until close to 29 weeks. This early baby is too small to feel all movement, so try not to stress. Baby can be in a position you don't feel as much.
I'm ftm and I didn't feel my little guy move until 23-24 weeks. And then it wasn't consistent every night until 27 weeks or so.
Im a STM and i am also 21 wks preg and i jus started feeling my baby move and i only feel him when i lay down and im reallys still