Pressure

Is it normal to start feeling pressure in your abdomen and uterus or both ? I'm only 17 weeks and I keep feeling this pressure on one side and I thought it was the baby but then I feel him/her kick my other side . or maybe it is the baby and he/she is just bigger than I think . I'm a first time mom so I'm just wondering , maybe it's because I'm so small and never had to carry this much weight before