Yep - it's completely normal. Some babies tend to be less active during the day - especially at this point in the pregnancy. Your movement, to her, is much like a rocking motion throughout the day and soothes her. When you're trying to sleep, she's not being "rocked" and is more awake and active. Don't worry - sounds like everything is fine.
It is normal. My baby did the same thing when I was pregnant. It seemed like she was kicking the mattress. On one of the ultrasounds she kicked the wand. The doctor was suprised! She is six months now and was always doing kicking motions. We showed the pediatrician and he recommended a jumperoo. We got it when she was 3 months and she loves it!
My OB doc said that is the number one question and it is normal.