-2 station????

I'm 37 weeks my midwife checked me and said I was 80% effaced, 1.5cm dilated and baby was -2 station, what does that mean? Does that mean labor is still really long off? I know it had something to do with the babies head, but she said that he was "really low" then proceeded to say about -2 station so I'm just wondering what that mean as far as potentially how close I am to labor, I've been cramping all day and she just said to call if it became more intense