18 month old... whining a lot

My daughter recently got moved up to another class at daycare. She's in with 18 month-3 years. She started whining bad like 1 month ago but the past week has been horrible since she moved classes.She throwing fits. kicking,screaming... I just try to find out what's wrong but a lot of times I feel like there's no real reason. I want her to go right she wants left..that's sorta thing. Took her to see Santa. She was soooo bad!!!! We do time out. She seems to enjoy it. A couple times I popped her leg cause she was kicking when I was trying to get her dressed. It did make her stop but I only want to do that if I absolutely have to. I've tried talking to her also and ignoring it (very hard) I am 16 weeks pregnant and I am getting scared about having her in this phase and a baby. Any ideas or suggestions?