Losing mucus plug + contraction at night.

Dj • Girlmom 💜 Sophia&Braelyn&Araya-Mae
Hey mamas. Im 31 weeks pregnant and for the past 3 days iv been losing my mucus plug with small cramps, kind of like poop cramps. But last night when i went to bed i had a single strong contraction that went from my lower belly to my back and down my hips. Baby is still wiggling around in there i just have a constint dull soreness in my left hip. Has this happened to anyone before?