Contractions 37 + 5 weeks

I'm 37 almost 38 weeks... and last night I started having contractions, I don't think they were just braxton hicks as they were painful like menstral cramps! they lasted about 2 hours, they stopped when I was about to call my midwife... I couldn't walk because of the pain. 
Is it possible they can stop and start again, if so when will they be likely to start again??? Is it normal for them to come and go for a couple hours until actual labour starts? I also feel very nauseous! I'm a FTM.