Sorry to hear you are having this problem.
Although it may seem like nothing with your connectivity has changed that may not be the case. We encourage you to post your signal levels, modem logs and FEC data from your modem to take a look.
Are you seeing buffering on all devices? Mobile and platforms like Roku or Apple TV?
Spectrum customers in multiple widely separated areas reported the same quality issues with the NFL broadcasts this past weekend. To me that points a finger back toward the NFL who provided the feed to the cable companies.