Thinking labor is close

I've been up since 11pm and just super uncomfortable. Could not sleep no matter how I positioned myself. Finally decided to get up at 2am to start timing my contractions. My contractions have been 4-7min apart for the last hour. Haven't lost my MP yet. I lost that with my first before the contractions started. I was already 2cm and 50% effaced last week at my OB appt. Hoping this isn't a false alarm. I think I'm gonna time for another hour before I call the OB.....just to be sure. Just thought I'd share since it's almost 3:30am and I have no one to share with