why are they sending me home!!!!

I'm 38 weeks and 6 days and have been having regular contractions for 72 hours. They were ten mins apart and now they have been 8 mins apart since yesterday. I was told to come back if I saw any type of blood and I've been losing my mucus plug in pieces for a while now. Well yesterday I spotted a bit while another piece of my mucus plug came out. Im 3cm and 50% effaced and I still got sent home!! I'm scared and infuriated. What am I supposed to do here??