Can early labor stop?

I went to labor and delivery last night for contractions 4-5 minutes apart for about an hour and a half. The doctor checked and said i was only 75% effaced and baby was -2 station. She told me I was in early labor and warned me it could take up to a couple days for active labor to kick in and to go back when i can no longer walk or talk with contractions. I cant stop worrying that it will stop, is it possible for early labor to stall out?