😔not happening for me

I see girls on here saying there baby’s are moving so much at 16,17,18 weeks here i am @20 weeks and don’t feel much of anything it also doesn’t help that this is baby #3 for me (but my last pregnancy w/my son was 3 years ago so maybe that’s why) . so I should of felt things earlier right? Idk if this is normal or I should go get seen it’s driving me crazy I lay as still as I can and nothing... every blue moon I feel like the tiniest little poke and then that’s it it’s gone ... idk if it’s worth going in I keep trying to wait and see if maybe the next day I will it’s so worrying for me.