Did i smother my kitten....?

ok i found this baby kitten under my house about a month ago.he was only 2 weeks when i found him. i fostered him and everything and his health was perfect..i think..well this is going to be hard for me to say cause it brakes my heart but this morning when i got up he was laying in my bed beside me and he was dead he wasnt breathing....well i went into complete shock..and im just tring to honestly figure out if i smothered him throughout the night..i mean i have been having a time with him the past week climbing up into the bed snuggling under my arm or pillow and i just dnt knw if thats what happened or not...he turned 6 weeks old just a few days ago and i thought his health was ok....im just tring to maybe put my mind at ease really...i just thought for certain that he would have meowed or scratched me or something to wakre me up because im not a hard sleeper i wake up easily....just looking for aome answers really something to make me feel a lil better i guess