I’m confused 😫

So I went to L&D; this morning around 4ish. Having contractions 5 minutes apart for more than an hour. They eventually subsided, and I was sent home with the diagnosis “prodromal labor” and told to come back if I felt a change. So I asked if I should wait until my water breaks, and nurse said no I should come as soon as I feel a change, cause I need to start antibiotics ASAP for GBS.

Now what change am I exactly looking for? Lol those felt like real true contractions to me. I was 3 dilated 80% effaced when checked this morning.

Also I have had some bloody mucus and chunks of mucus after I got home. Do you think it’s cause of the cervical exam?