It is useful to remember that this whole idea of rebirth is no more than a metaphor, a theory, a particular way of looking at things. This does not mean it is right or wrong, rather that it is a conceptual framework that, as all concepts, does not indicate anything real but rather a way of thinking.
This appreciation is at the heart of Buddhist understanding. From an enlightened, nondual Buddhist perspective, in reality, you do not find enlightenment or anyone to achieve enlightenment. You find neither rebirth nor a circle of rebirth. Resting in natural awareness, the end-point of Buddhist meditation, there is clearly no-one to go anywhere nor even to stay. This is not different from enlightenment.
Resting in the unconditioned mind, all of this is not apparent. From here the answer of the Zen master, “When hungry, eat. When tired, sleep.” becomes evidently clear. Accordingly, I suggest not worrying unduly about all this. There are many ways of looking at things, but the world is as it is.
As the Buddha is reputed to have said, “If someone needs something, give it to him.” Just look after yourself and others as you can and the rest will take care of itself.
Wishing you a happy, calm and fulfilled life.