Maybe baby??

So the past few days I noticed when I'm laying on my back randomly I'll feel a little tightness and pressure on my lower abdomen right above my pubic bone, and when I put my hand on it it almost feels like a hard ball but disappears after a minute or two. It has happened on both the right and left sides. I did feel a small kick 4 or 5 days ago for the first time. Could this be baby pushing up against the tummy side of my uterus????? It's the weirdest feeling! Currently 17 weeks!