Signs of labor..?

Is it possible to have no signs of labor one day, & the next day your body does a drastic change far as giving off so many signs? Or do you normally start feeling things a day or days before? Just curious....almost 40 weeks & I have no signs on baby 👶🏽 😞 Although, I been having small Braxton Hicks but only before bedtime for some reason 🧐