Yesterday my little man was awake and happy and today he has really done nothing but sleep. Is this…

Yesterday my little man was awake and happy and today he has really done nothing but sleep. Is this normal for 6 weeks old? My mother in law had him for about a half hour today and he did nothing but whine and cry until I got there. Then he quit crying. Is this a growth spurt? Or just need mommy time? Help!!!