Trying to change my littles sleep habit....

So I have an almost 8 week son- he sleeps great until about 3 am and then he is up at 3, 4:30, 5:30, 6:30, and up for the day by 8. We usually try to put him to bed by 8 or 9 and I’ve even waited to put him down to see if that changes anything and it doesn’t. He eats about 4 ounces at 3 am the first time and then only 2 ounces the other times he gets up. I just feel like his sleep is backwards!!!! What can I do - he’s formula fed so I’m not sure if it’s just not enough. If I feed him too much he just pukes. I just know this can’t continue and me be able to go back to work :(