My son is now one week and a day old 
We have recently switched to formula, I really tried to breastfeed and did until I couldn't do it anymore.
He is doing very well with formula, I'm using similac.
He usually wake up every 3-4 hour and will eat about 3 oz, sometime a little bit more.
But today he has been sleeping longer and eating less,
He'll sleep for 5 hours and so and when he wakes to eat he is only eating 2-3 oz.
but then he will sleep for two hours and eat 2 oz or so.
I'm afraid he hasn't been eating enough,
Family members have told me that he will wake when he is hungry, and eat until he is full.
but is this true?
If not should I wake him to eat?
We have recently switched to formula, I really tried to breastfeed and did until I couldn't do it anymore.
He is doing very well with formula, I'm using similac.
He usually wake up every 3-4 hour and will eat about 3 oz, sometime a little bit more.
But today he has been sleeping longer and eating less,
He'll sleep for 5 hours and so and when he wakes to eat he is only eating 2-3 oz.
but then he will sleep for two hours and eat 2 oz or so.
I'm afraid he hasn't been eating enough,
Family members have told me that he will wake when he is hungry, and eat until he is full.
but is this true?
If not should I wake him to eat?