Irregular Contractions?

So today I had diarrhea and after I went potty. Some more of my mucus plug came out and before I got up from sitting down I started having contractions. I had them very irregularly for about two and a half hours, then I laid down to take a nap. No contractions, or strong enough ones that I could feel while I was asleep. I got up from my two hour nap and started having them again irregularly, plus lots of pressure and pain below my stomach in my pelvic area and sometimes even going into my back. What is happening? I have also been drinking water and it doesn't do anything. I'm 39+5, on Wednesday I was 2-3cm, 90% effaced, but his head was still high. Any advice?