He used to nap 45 minutes, then it went to 30 minutes, now for the last week it's been 10-20 minutes... He's 4 months old! What's going on? Nothing has changed in his daily routine or bedtime etc. Because of the short naps throughout the day by 5 pm he's exhausted and falls asleep in his bouncer chair and is out of it for 2-3 hours! This is not good but if I don't let him sleep in his chair he'll pretty much cry until it's his bedtime. He sleeps fine at nights usually but this last week he's started waking up more. Help!