Don't be scared love smile. It's okay. There are a lot of different pain relievers for labour. As suggested by a couple of women and from first hand experience myself, warm water is absolutely heaven (either a bath or shower). Positions can also help minimise the pain you may experience (such as squatting, rocking, leaning over a bean bag, sitting on a yoga ball). As for drugs you can use during labour, they are fairly safe. The gas (nitrous oxide), they give you is short acting as soon as you stop sucking on the mask or mouthpiece it is gone within seconds out of your system (It can make you a little high or some women it can make them feel sick just depends). The pethadine is great for taking the edge of the pain, the down fall is that you cannot have it within the last 2 hours of the birth (approx from about 8cm) as it does cross the placenta and can make bubs a little drowsy after they are born (it will not cause any other symptom but that). If you want total pain relief (where you feel nothing) an epidural is the next pain extinguisher. This causes no harm to the baby and is great is you would like to be awake for a C-section. The only downfall to you with this is that you may not feel the urge to push or may not know how to push and this increases the chance of an assisted delivery (small percentage), but with the right coaching you should be okay. They also have walking epidurals these days as well. Other narcotics such as panadol, panadeine and panadeine forte don't really relieve pain if you are in true labour as they are a different stream of pain killers.
Make a birth plan if you haven't already done so with what pain relief methods you would like to try and in rough order. Don't make any decisions until the day, but a birth plan will put you in the right direction.
I have had two children and having a third on 8/09/06, and with both of my boys I had no pain killers just used water, hot compresses, music and aromatherapy. I have also in my second year of nursing, so have some experience with drugs and precautions, and also of what drugs will do.
I hope this has been helpful to you.