hello moms Im very new here but I need some help and advice plz

I recently took a blood and urine test both were neg. however Im feeling crampiness, muscle tightening, fluttering feelings like kicks. Most of all when Im lying on my back, i can feel like  a hard round ball-like figure in  my stomach and it seems to move to the left sometimes but stays mostly on the right side. has anyone had this to happen?