Anyone else feel baby then dont?

I am currently 18 weeks 6 days. And for the past few days I've felt the baby lightly every evening but only when I'm sitting or laying down. I havent felt much movement going on or to none at all yesterday and today. I mean everyday I felt the little taps and swooshes but now I dont. I'm just a bit scared. Does this happen to anyone else? Like are there days where you'll feel the baby and then suddenly stop? I am overweight too so idk. Anyone else?