Am I going into labour? Do I need to call my OB?

Ill start off by saying im 34 weeks. I woke up 2 hours ago with lower back pain and menstrual like cramping. I got up to walk around and it didnt help. It just hurt so bad I decided to tak a bath and still painful but started coming and going every few minutes with just slight cramping inbetweent he painful cramping. This has been going on for 2 hours straight now and its painful. Is this labor? Do i need to call my OB?