Having my baby 4weeks early? ?

I stayed the night in the hospital last night because my contractions were 3-5 mins apart. I also had a doctor appointment on Wednesday and my doctor said I was not yet dilated. But last night I was told I'm 3cm dilated and 75% effaced. They sent me home this morning after giving me some medication last night to make me drowsy and pass out. That slowed down my contractions and lowered my blood pressure. I am still having contractions but I was wondering what may happen if I have her 4 weeks early. Please help!