Baby movement

First time mom here I’m 20 weeks today the only thing I can say I’ve felt is like a pulsing feeling or subtle thumping feeling or like a quick subtle feeling mainly at night when I’m really focused. But as far as that I haven’t felt any strong movement or noticeable kicks I know everyone is different but it’s making me nervous. I seen a mom say the other day she can already feel her baby from the outside and can’t even sleep at night with how active baby is also at 20 weeks. My OB hasn’t mentioned it but went to the ER at 14 weeks for symptoms of blood clot (thankfully wasn’t) and then I noticed my discharge papers said anterior placenta OB hasn’t mentioned it yet I’ve heard that can make you take a while to feel baby? I go Monday for my 20 weeks appointment should I mention it to my dr? Is this normal or should I be nervous