See
(331872.3) for some of the big reasons your merch may have dropped off.
From my observation with my own team, being a top of the table team in Division N and being a bottom of the table team in division N-1 (the higher division) results in fairly similar Team Sales value, all else equal... maybe a few thousand dollars better in favor of the bottom of the table team in the higher division. Either way, it's a small enough gap that it can easily be overwhelmed by the loss of All Star jersey sales and a poor week of jersey sales if your top salary players underperformed in game 1.