To get a better understanding of what the analysis is trying to say, you chould check out the
FAQ linked to at the top of the report.
Briefly, the NM data is the design criteria - having +10dB at the receiver will yield reliable reception. In your case, yes, you do have 10 strong signals, including one VERY strong signal. Experimenting with an indoor antenna was not a bad idea, but the mistake was using an amplified one. The strongest signal, WBXX, was probably overloading it, causing distortion to almost every signal.
You don't need a high-gain antenna, but you do need VHF/UHF. Some good choices are the RCA ANT-751 or the AntennaCraft HBU-33. Good luck!