Help with 1.5 month old

Connie • Unless someone like you cares a whole awful lot nothing is going to get better. It's not.
I'm a FTM and I'm having a lot of problems with getting my son to sleep at night. I exclusively pump and feed him from a bottle. A lot of people are saying to add ceral to his night bottles to see if that would work. My question is, would it be okay to mix a rice ceral with breastmilk? I've not tried it yet and wanted to make sure that it would be okay to do that. My milk is pretty creamy and heavy for the most part without adding anything to it and I'm sure he's getting everything he needs. I just have a serious issue with him waking up constantly at night and wanting food, but not eating it all. I've tried adding more milk to his night time bottle but he just won't take it all. He's great during the day and have no issues then, just at night. I produce enough and do not want to supplement for night feedings if I don't have to. What are people's thoughts? What other options could I try?