We just put up at 18X48 pool and now that it is almost full with water you can see one side is lower than the other and it is putting pressure on the lower side. It is probably about a 6 inch difference around the pool in water levels. Is there anything we can do to fi this problem without emptying the pool. It cost us quite a bit to fill the pool and I really do not want to empty it? We are trying to put sand bags under the lower side? Or should we try to dig on the higher side?

Not only is it impossible to fix this with water in the pool but you will need to almost totally undo the installation. Your pool must sit on undisturbed base that is perfectly level, you'll be digging out that high side.