[mousey]

your ph is just fine. Mine is 8.2 out of the tap and despite having lots of wood and plants in my tank it does not lower the ph very much. There would be some lowering with plants and wood and from the debris from plants,but not a huge amount.
My goldies are just fine in it.
Try cutting back on food for a few days til the ammonia comes under control. Goldfish seem to be always begging but you can feed daily or alternate days with no harm to them and in small amounts!!
Complete water changes are not too good for the tank I found out --they actually can cause a mini spike in ammonia at the best of times and since you are reALLY DOING A CYCLE AGAIN i WOULD JUST DO 25% EVERY SECOND DAY AS WELL AS USE EITHER Seachem PRIME or Ammo lock. Neither mess with the cycling process but do make it a bit more comfortable for the fish. If you can't get Prime throw a bit of aquarium salt in the tank when the nitrites spike. It helps the fish so that the Nitrogen does not go into the blood stream.