bad bowels! 38 weeks

I'm 38 weeks and 3, and I have bad bowels again I can't get off the toilet.
Haven't eaten anything different
No sign of labour
This happened when I was 36 weeks and when I went to get checked they said his head was engaged and could be my body getting ready. (I also had bad discharge a lot which I thought could be my waters) 
I'm off out today anyone got any advice what I could do in case anything happens labour wise?!