Well the processing of ammonia is only 1 part of the cycle. After your ammonia gets converted in 24 hours, then you can expect a nitrIte spike with the new bacteria, and then you wait a while until those levels drop. It seems you skipped that step. The NitrIte drop takes longer imo (it is for me). Once you get 0 ammonia and 0 nitrItes in 24 hours, then you are cycled. You added the fish at the 2nd stage of the cycle and not when it was finished, which is why you are having the issues you are now.
Essentially you are now fish in cycling, so keep up on those water changes and wait for the nitrite bacteria to take over and complete the cycle.