Did you do a water change? Only way for nitrates to drop is through water change. There as some ways people do it in well established tanks but in your case that would be the only way. Either that, or you may have messed up the test somehow. I would run the nitrate one more time. Based on the Am and Nitrite, I would say you have a colony of BB but it may not be a strong colony yet. I would continue to dose with Pure AM for a while longer, trying to bring it up to 4ppm each time. Once Am and Nitrite disappear quickly AND the nitrate climbs and stays high, you should be good to do 20% water changes until you get the nitrates below 5 but preferably close to 0. Then you can SLOWLY add a couple of fish.
Since my tank is a birthday present to my wife, everything I spend going forward is just an extension of my love for her right?