I would guess you might have something to hide from your family, whatever it is. You say you regarded it as a pet at first, and then find it scary. I don't claim to have any bearing on anyone's life here outside of this little dream paragraph, but if dragonflies have any sort of significance to you as they did to me as a child, it would seem like you've got an artifact from childhood which would today seem inappropriate, disgraceful, or something similar.