nighttime 7 week old

My son is 7 weeks old. Once we stopped waking him every 2 hours to eat, he'd sleep 4-5 hours on his own at night. However, around Christmas he started waking up every 1-2 hours and has every night since. He wakes up and acts like he's starving - I breastfeed and supplement, so I know he's getting enough - after he eats he'll fall asleep fairly easily. Put him down and he's back up in 1-2 hours. During the day he eats constantly, but it's very inconsistent - 30 minutes or 2 hours. For example, at 5am he had 6 ounces of formula (I was pumping, hubby fed him) and woke up at 6 and ate off me and had more formula. Then ate again at 8 - off me and more formula.