If all the other suggestions don't work, you might want to discuss this with your pediatrician. My son did this, and it got worse instead of better. Eventually, he was incapable of sleeping in daylight, regardless of the amount of sleep he had the night before. We finally completely blacked out his room. Daycare was a real problem. I asked his pediatrician about it every time I took him to the doctor, but I was repeatedly told it was "nothing to worry about" and he would "grow out of it." He didn't. I kept wondering what on earth I was doing wrong. It turns out he has severe sensory issues, including a sensitivity to light. He's ten now, and still can't sleep in daylight. Sensory issues aren't common, but it's something to keep in the back of your mind, if you've tried everything else without success. Had I known about it when he was a baby, it might have saved me a lot of frustration and self doubt, and I might have pushed harder for answers.