So the lower side part of my belly hurts its uncomfortable and feel kinda painful when I move since…

So the lower side part of my belly hurts its uncomfortable and feel kinda painful when I move since yesterday maybe its cause the baby is getting bigger. She just kicked me there and it hurts a little. I'm never felt pain when she kicks before. What could it be? And I do have a doctor's appointment tomorrow I have so many unanswered questions..