My 10 Month Old Son Wiil Take A Nap Maybe

my 10 month old son wiil take a nap maybe for ten mins and then wake and start crying and when i get up to get his bottle he will cry because i am leaving the room. also my 3 year old son has been asleep since 2:30 or 3:30 today and when i went to go pick him up from my moms house he did nothing but cry non stop until we got home he ate supper and then fell right to sleep and is still asleep is this normal for them