Severe back pain

Alright ladies this is my 3rd LO. With my son a day before I went into labor (my water broke) I had the worst most severe back pain (I just could not get rid of it). Well I am currently pregnant with my 3rd a girl and she dropped yesterday and I'm having that same back pain as I did with my son not as severe yet but it's not going away  no matter what I do. My due date is June 19. Thoughts?