My DD is 4 1/2 months old,and is on a 3.5 easy, She sleeps very good at night, but for her naps I put her down and exactly 45min later she wakes up, and I have to go in there and pat/shh back to sleep, she does this every nap, and when I put her down for bedtime she does it once, then she's good for the rest of the night. Why does she do this, and how can I prevent it from happening anymore?