Am I near?!

I am 36 weeks and have been experiencing a significant difference from my past 2 pregnancies. Last night I had a dull constant back ache that did not subside with a constant menstrual cramp. I've been having Braxton hicks along with all of this. The cramp seemed to radiate down my hips and i couldn't seem to get it to go away, even a little. But never got "stronger" if that makes sense. I had diarrhea in the middle of the night. I have not lost my mucous plug. This morning I've already had more BH but my back feels like I was hit by a train, it seemed sore! I am not sure if I should call the doctor and get their advice or if I should wait and see how I feel today. I don't want to make a trip to the hospital only to be sent home soon after. What are your thoughts? I was 2 weeks early with my first and induced at 39 weeks with my second. My first is 6 years old so this all seems new again.