Behavior: Playtex

14 Month Old with Negative Change in Behavior

My son has recently been more moody then usual. He is throwing tantrums which he hasn't done before. I am also trying to introduce him to the sippy cup. He throws it and crys for his bottle which I am trying to reserve for naps and bedtime only. Is this behavior normal? Also any advice for transitioning to a sippy cup for a bottle attached little guy?