Baby or Gas?

Nikki • Mother of two angels & 1 rainbow baby, Lillian.
May be a strange question but I'm a FTM. I'm 20 weeks but doc said wouldn't feel movement for a while because of where placenta is, so don't worry. The past couple of days I've been feeling funky stuff, but can't tell if it's baby or if it's gas. It may be hard to describe, but what do early baby movements feel like?