signs of labor

So, I will be 39 weeks on Tuesday. A few days ago at my appointment the Dr stripped my membranes. Ever since then I've been doing things here and there to see if I will go into labor. Since yesterday I have been having light period like cramps (stomach tightening as well). Also my thighs and pelvis are kind of crampy I'd guess you'd say, like they feel when your on your period. Does this mean labor is near? Can someone tell me what a contraction feels like and how I will know.

Also I'm having trouble emptying my bladder it takes forever and I have to tilt every way to get it out. I've also lost my mucus plug I believe, I've lost so much mucus I don't see how there could be anymore left lol