Regular contractions, not dilating?

Has this happened to anyone else? I had regular contractions, 3 mins apart for 11 hours and didn't progress at all. I lost my bloody show a few hours after the contractions started and went to the hospital. I was there for 5 hours, and could clearly see the contractions coming every 2.5-3 mins, and were so intense they were shooting off the chart. But every time they checked, I was still only 1cm dilated and 70% effaced. I'm so frustrated, I honestly thought this was it but was sent home. Anyone else have regular contractions and not be in labor? Or lost their bloody show? I really wish I knew what was going on with my body.