Help all the sudden my 3 month old is waking up in the middle of the night?

At 10 weeks my baby boy that is feed starting sleeping 8-9 hours a night. All the sudden 3 days ago, he started waking up at midnight, I would put his pacifier in his mouth and he will put himself back to sleep you can tell he is sleepy. Then he will wake up at around 4:00 which is his normal time to eat and it's like he is starving. He use to eat and go right back to sleep now I am having trouble with him wanting to go back to sleep immediately. He is a hefty boy, at 8 weeks he was 13.14 oz. He has been taking a couple of really long naps during the day, so he is not eating as much as he was. I don't want to get him in the habit of waking and feeding if he does not need it because he has been sleeping through the night for 2 weeks and now it has changed. any suggestions or has anyone else had this problem.