When to go in for labor ?

I had my appointment this morning and had a membrane sweep. I am 39 weeks and 5.5 cm dilated. Mild pain with contractions but I can’t really tell because my back hurts. I do feel pelvic pain, but I habit been having that for the last month. Lost my mucus plug over two week ago. When do I go in? Doctor said if I feel painful contractions or if my water breaks I should go. But I can’t tell the pain level? I don’t want to go too early and just be sitting at the hospital and I don’t want to go too late and risk having baby at home or in the car because I am not ready for that.