Is this labor?

38 weeks and 2 days today. 3cm na since Wednesday. May lumabas na rin po na mucus plug sa akin, brownish pinkish na may transparent basta parang sipon. Lagi na masakit lower back, naninigas tyan & may dysmenorrhea feeling pero tolerable pa din at pawala wala pero babalik din. Nag start na din ako mag insert ng primrose (may reseta ng OB) yesterday, 3x a day. Labor na ba ito, waiting for active labor?