Feed or not to feed

When your little one wakes up in the middle of the night how do you know whether or not to feed them. Before we hit the four-month regression my son was sleeping through the night, now he wakes up once or twice. As soon as I feed him he goes right back to sleep so I don’t know if he’s waking up because he’s hungry or if he’s just going back to sleep because I’m nursing. Sometimes I can just turn on his music and he’ll fall asleep without eating and other times I have to feed him in order for him to fall back asleep. I just don’t know if I should continue to feed him every single time he wakes up or if I should let him learn how to self soothe again to put himself back to sleep.