Once your amm and nitrites go to 0 and you're seeing nitrates build, it's cycled. It is possible to see nitrates while still building amm and nitrites. That means you have some of the good bacteria, but there are not enough bacteria to handle the amount of waste going into the system. The good news is that once you see nitrates at all, the good bacteria will be faster at keeping up with an increased bioload.
Now that's all true unless you've got live plants. In which case, you might not see the nitrates building. If that's the case, you still need to do at least a 25% water changes weekly to replace the micronutirents in the water for the plants. But I didn't see if you said you had live plants or not ...