Sent home with contractions 2-3 minutes apart and 3 cm dilated? Is this normal!?

Okay, so my contractions started at 2 pm yesterday afternoon. I waited until I couldn't take it anymore. Finally I went in at 10pm, after a LONG day of strong contractions that felt like period cramps and really bad back pain, tightening uterus/stomach, and I was having loose bowel movements throughout the day. I do take pain rarely easy they said they were indeed contractions, and that I was at a 3. They checked again an hour later and still at a 3. They told me to come back in when they were stronger. Stronger? They are strong! I've never been pregnant or in labor! I can't even lay still or stay in a position! I'm scared!