Multiple letdowns (edit- 8month old)

Daughter has been nursing for like an hour almost lol, bedtime so, and every time she starts dozing my letdown starts again, snd the longer she nurses the more frequently it’s happening. Like every couple minutes now. Is it because it’s basically empty and it’s just letting down what ifs producing again?

She nurses to sleep, but having a rough evening. Just curious why it’s getting closer together? This boob is gonna be pretty damn full from all this nursing 😂