Labor symptoms?

So I've been feeling really weird. I was checked two days ago and no dilation. Then last night, my mucus plug comes out but no blood streak. Yet today I keep having contractions and feeling like I need to poop all day. And to add more to that, I've had pain where my sternum (not heartburn, more like a dull pain) and have been very nauseous. Is this normal? Am I going into labor? Any of you ladies experienced this prior to giving birth? By the way I'm 38 weeks and 3 days.