Miralax while pregnant?

6 weeks pregnant but I don't have my first appointment for 3 more weeks. I have been so constipated (sorry for the TMI). I called my doctors office and they suggested Metamucil, colace, or Miralax. I've taken miralax before I was pregnant for occasional irregularity and it worked fine but I'm still nervous about using it while pregnant đŸ˜­ has anyone used it and do you recommend?