Are these real contractions? CONFUSED!?

I have had false labor/BH in the past with this pregnancy (Due the 26th of this month). But today, about every ten minutes, I feel these horrid back pains that wrap around to my stomach. There is no pain at all in my stomach, but it tightens inwards, and I almost feel like I want to push (as if going to the restroom, lovely as it may sound). Yesterday I had an upset stomach all day, and loads of diarrhea (TMI again, I know). Any help? Luckily, I go to my OB in a couple of hours anyways, but I'm so confused! I don't want a third false alarm! ((This is my first pregnancy btw))