Scared of bowel movement - what can I take for this?

I haven’t had a bowel movement in 5 days and I’m 36 weeks pregnant.

The last couple of times I’ve tried nothing has come and when I have been successful it was painful and took me about 20 minutes.

I’ve taken prune juice and more water. Not sure if that is enough.

What can I take for this? I am terrified of when a bowel movement will come now.