You should do whatever you gut tells you. If you think labor might be starting early, go to L&D. The worst they can do is tell you they're Braxton-Hicks contractions (although those are not at regular intervals) and send you home. It's better to be safe than sorry. If you are in pre-term labor and they catch it early enough, they may be able to stop the contractions. Don't let them tell you over the phone to stay home if you think you are in labor. Go with your gut.