When you first start to feel movements it can be sporadic because your baby is still really quite small & could be kicking / moving toward the placenta & you wouldn't feel it IYKWIM. As bub gets bigger you will feel movement every day, lots of times & it's only one you feel regular movements that movement stopping can be a concern
What Sarah said!
I've felt 2 kicks so far. Mainly because bub is still so small, and also because of the position of my placenta. It's at the front and bub is behind it, so any movements bub does I don't really feel.