Yes, you are just too impatient. Marco rocks are known for lots of dead material that will spike a tank. Just let it sit. The nitirites will come down and the nitrates will spike. It's the circle of life (in the Nitrogen cycle sense anyway).
You do not need to add any bacteria for this to happen. They will get there and grow.
DO NOT DO ANY WATER CHANGES! That actually will prolong the cycle time.
DO NOT TEST pH, Alk
or anything but Ammonia, nitrite and nitrate.
When the nitrite finally falls to 0 and the nitrate is showing then you can do a 50% water change and start testing pH and Alk
How old is your nitrite kit?
You may want to take a water sample to the lfs
to have them check it too.