Braxton hicks or early labour?

So I'm 37 +4 today and this morning I lost what I think was my mucus plug, I'm having quite bad back ache and cramping in my lower stomach ( like a constant period pain cramp it doesn't come and go )along with the odd twinge/pain down there. Could this be the start of anything? Do I just wait it out or do I need to contact triage or anything?