nitrite level

[William]

I thought I had my 30 gallon tank cycled and was going good, but for the last three days my nitrite level is 1.6-2.0 mg/l! My ph is 7.5,amonia 0, GH 13, KH 9. I have 6 neons less then an 1" 2 mollies, 2 swordtails, 2rosie barbs, 2 bala sharks, 2 clown loches, 1 catfish, 1 freshwater ell. Am I over stocked? I have been doing 20% water changes every other day. What can I do and how bad is this for my fish?
Thanks
William