cannot poop by myself

Currently 13 weeks. Had bad bowel before this pregnancy. But currently if I don't take milk of mag and use an enema I won't poop at all. I do that once a week, so I'm legit only going once a week. I'm so uncomfortable but I never have the urge to go. It's like it's all just sitting there waiting. What do I do!? Any advice ladies would be helpful. I'm so uncomfortable and can't live on milk of mag for 6 more months.