Too easy to fall in sleep

I think I am really too free at home. I wish I could spend more time with my children at night. I often fall in sleep before my children if I am too free and just lying on the bed. haha ..sound very funny, right? No joke, I fall in sleep very easily. Yesterday, I was playing with my children on bed. and when them turn around and play a side, I am starting to feel sleepy already. Then, fall a sleep even they are playing beside me. haha