This early in pregnancy your baby will constantly be moving sides, switching positions and moving around. When they are much larger in the last trimester they move a lot less due to less room.
During my last ultrasound my son was head down, feet up on my right side. During that same ultrasound he moved to the left, was sideways and waiving. This is a fun stage for them. I was 15 weeks my last ultrasound :) I have another scheduled in about 3 weeks