Contractions?

So since 8pm last night I started getting dull back pain/cramping. Almost like what you would have if you ate something and it wasn't agreeing with you. It would happen every 15/20 minutes. The pain pretty mild. Since then I've been waking up periodically through the night noticing the pain. At about 1am I started tracking it. It happens about every 8 minutes now and the pain is a little more intense. At first I thought it was just bad gas or maybe the food I had for dinner not agreeing with me but now I wonder if it's contractions. I was in L&D last Monday and it was a false alarm. I was having mild contractions and dilated at 1cm. I had an appointment on Friday and no change in dilation but baby is engaged. I only really notice it when I'm laying on my sides. I tried sitting up to see if I notice it and I don't. But as soon as I'm on my sides it starts to happen again. I'm 39w 1day now. Just not sure if these are real contractions or not