To understand which channels are having problems, it would help if you referred to them by call sign and real channel number.
The CM7777 is a good amplifier in selected applications. It's not appropriate for you because it is intended for weak, fringe area signals and would very likely overload in your situation. WATC, real channel 41 is only 1.1 miles from your location. They transmit 330,000 Watts (ERP). That is a lot of signal power at your location.
I would suggest that you consider mounting the antenna higher and add a
C2-VHF-Reflector-Assembly which will improve the antennas ability to receive real channels 7 through 13. Avoid aiming the antenna at buildings or trees if at all possible.
You may also consider replacing the antenna with a more directional antenna such as the Antennacraft HBU-33 or Winegard HD7694P. But before doing so, I would experiment with better mounting locations for you existing antenna.