Not sure if cramping or contractions?

The past few hours my back has felt achey of sorts. I get some tightness in my upper and lower back every now and then, and sometimes my stomach feels like there's so much pressure on it. I'm almost 38 weeks and Wednesday I went to the doctor and he said he could feel her head and I was 1cm dilated. I did have sex earlier. I was thinking of just taking a bath to try and soothe the pain, but I wasn't sure if that was a good idea. Any idea ladies?