See, you can't force sleep on you. If baby sleeps that does't mean that you are also sleepy at that particular time or will get sleep. Sometimes, you long for that time and think that when the baby will sleep I will also sleep, but somehow when the moment arises, you are not able to sleep. So, when you are not sleepy and keep trying futilely you get more tired than feeling fresh.
I guess, if you feel sleepy with the baby then sleep, else just relax, surf the net, watch a movie or do whatever relaxes you.
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