Ghost kicks or what?

Hi lovely ladies I'm 21 and had my first boy last may,,, 30 days of postpartum bleeding and no periods yet,,, I'm breastfeeding and I feel something like baby kicks I tested 3 time 3months ago but came out negative ,,, what does ghost kick means and is it normal to feel kinda baby kicks after 5-6 months of delivery???looking for advice and guidance

Thanks in advance