4th baby and still no movement

Hi has anyone had a similar situation. This is my 5th pregnancy but 4th baby and with my other 3 children I started feeling them around 14/15 weeks one of them had an anterior placenta aswell but this time around I'm 18 weeks and have felt nothing. All scans I've had were good and I've heard babys heartbeat etc but not feeling baby is freaking me out with me feeling my other children alot sooner. Has anyone else ever had this? Any help would be greatly appreciated thank you in advance 😊