Labor? (Kinda long)

For the past couple of hours I have had cramps like period cramps they aren't terrible and they aren't constant. I am also having diahhrea and back pain. With my daughter I didn't have back pain at all I just had contractions. I also keep getting lightheaded when I stand and feel like I can't breathe. I know you ladies aren't doctors or anything but have you ever experienced anything like this? I already called my ob he hasn't called me back. I figured while I waited I could ask if any of you know what this is.

Thanks in advance.