Legitimate Concern or Not?

I need some input here. I am not sure if it is my imagination or it's really happening. I am 29 weeks and 2 days and I think my baby is starting to drop already. She is my second child, and recently I have had more pressure in my pelvic region as well as lower back pain (back dimple area) only on my right side. I am not sure if it is from her growing so fast or its her dropping. I see the doctor for a check-up this coming Tuesday.