My mother was a nurse and she taught me that your appendix is situated right above the right hip bone about 2 fingers next to each other.
What concerns me is the burping and nausea. You could have some gallbladder problem also. If you have sharp pains in your back right under your shoulder blades then it's the gallbladder.
I am in the US and don't know anything about England's NHS, but I'd call them up and do whatever you have to do to get into the doctor's before you have to be admitted into the Emergency Room.