Try not to worry, it's just your hormones making you feel like this. We all worried as first time mums as you are entering the unknown. Wanting a child is the first step to being a good parent.
its amazing what your body and mind can do when it needs to, if labour was so bad we would all be only children with no siblings. Try to relax you will have many options available in terms of pain relief to help you, if it helps with my first child I asked for an epidural and watched the Simpsons quite happily for hours after.... I ended up not feeling a thing..... Almost bliss! X