To answer your specific question, I have no knowledge of a change... I don't know one way or the other. I could speculate that a TV or FM station has come online or increased power recently... but that is only speculation.
I do know, as JC has pointed out, an amplified antenna is not indicated by the information in your TVF report. Amplifiers have there place. Your signal conditions argue against an amplified antenna. The powerful signal levels at your location could easily overload many amplifiers including those built into small antennas such as yours.
If you are still having problems after trying different locations and adjustments of your existing antenna, You may need to consider replacing it with an antenna that is non-amplified. Here is a list of
indoor non-amplified antennas.
If I were in your situation I would install an RCA ANT-751 outside, aiming SSE. I would expect that type antenna to receive enough signal power to easily drive eight sets with no amplifier required. The antenna suggested by JC is another option which would provide even higher signal levels.