Problems with my nitrogen cycle?

Hello, I have bought my first fish tank last March, and have been unable to start the nitrogen cycle. In the beginning I have made the mistake by adding too much fish too the tank, and most of them have died. Now recently 1 of the shops here sold me API cycle, and I have used this in my fish tank, and within a couple of days my ammonia and nitrite and nitrate apeard, then when my amonia and nitrite levels showed up as zero, I have added a clown loach and a synodontis cat fish to my surviving 4 neon tetras 4 silvertip tetras and 2 platties, and last week i have added a couple of java ferns. The problem I have now is that my Amonium levels are up to 2ppm, no nitrite levels and low Nitrate levels, is this bad, as the shop advised me to stop water changes, but I am worried that I will loose my fish, PLEASE HELP.