7month old vomit

Jacky • 24

Why does she throw up randomly? It’s happened before maybe on 5 different occasions. It’s always at night. I’m asking because it just happened right now. We woke up around 6am she ate, she’s breastfed. I woke up at 8 bc I heard her gagging I flipped her over she was throwing up. It’s not a little spit up, it’s a lot of milk. She’s started solids but she’s not eating a lot of it yet. She’s not throwing up any food it’s milk only. I eat normal I don’t see anything that could of triggered it? This has happened other times before in the middle of the night. What could it be? When she was nb she struggled a lot with spitting up but it was extreme I was always concerned thinking it was reflux but the drs never cared bc she wasn’t loosing weight. It eventually went away around 5months. Could she just be too full? She usually eats and falls asleep and I let her sleep, I don’t wake her up to burp could it be that?