Not sleeping through the night

I have read many mothers have their babies sleeping through the night. My son just turned 5 months and he slept through the night may be 10 times since he was born. He is BM fed but at night I give him formula. Lately he wakes up 1 hour after I put him down. This drwsy thing does not work with him. He must fall asleep with a bottle so he can sleep; otherwise he stays awake. Should I be worried? I'm just reading how many his age are sleeping through the night.