Hello can anybody explain me

How its cervix about?? I dont know anything i went to hospital today since i start bleeding like mocus and i also have 4 dilated im 37+3 weeks and they felt baby head already i have contraccions every 10 min i dont feel anything and they send me back home why???? They said somenthing about cervix but how if the already toch baby head im confuse please help me they said to go back if water breaks or have painfull contraccions but this my 3 baby and other 2 didnt feel contraccions till they brake my water how im gonna know when to go back so i can stay with out they sendimimg back home????