belly discomfort

I am 18 weeks 3days and I definitely feel the baby growing. I was wondering if anyone else felt discomfort in their upper abdomen some days when baby has been growing. It is very mild, and usually doesn't last all day. I often wake up and feel like baby pushed my organs up a little more which just kind of gives me an upset stomach feeling. I assume it is pretty normal. Just curious if anyone else has encountered this! it makes me happy to think that baby is growing and healthy!