As the PP mentioned - like period pain x100. It is a "working" pain, and your mind has a huge impact on how you handle it! I never really believed that until I had my second daughter. Believe that you CAN do it, and ride the contractions like a wave - they come in, and they go out. Breathe slowly through it, and think about your baby getting closer. Do your best to relax your body and work WITH the contraction, instead of fighting it. I highly recommend getting in the water in some way - the bath, the shower, whatever. Walk as long as you can, and stay upright as much as possible. Moving around really helps keep things going. Also, make sure you will have good support during labour. Maybe consider a doula?
All the best!