Anyone getting phantom kicks?

We’re all obviously 5 months postpartum or close to it, I’m still feeling kicks or movement in my tummy and I know I’m not pregnant cause before leaving the hospital when my son was born I got the arm implant birth control and after feeling these kick like movements I took a pregnancy test which was negative. So I’m just wondering if it’s still possible to feel those phantom kicks this far along into postpartum or if it’s something I should mention to my doctor?