Contractions?

mls11

So this afternoon for the last few hrs I have been having some tightening and mild pain in lower abdomen. It has seemed to get a little stronger over time, but the frequency is about the same (3-4 min, but not always very strong). I have continued to feel them while standing, sitting, or laying down. I haven't had any bloody show or anything, but I am wondering if this could be the start of going into labor! I am almost 40 wks. Any thoughts?