Sometimes red packs can be accumulated even if the team is competing.
I don't buy packs and let my teams to promote in every season. As I remember, both my teams used to keep hundreds of tokens. At present, my L21 team still keeps 183 red packs. This is close to its average in last few seasons. My L13 team's no. of red packs just raised back to 76. But in last few seasons, the balance fluctuates from 0 up to 40.
I feel bad for you about the injuries. I just want to remind you to carefully manage the red packs, and think twice before applying red packs on short term injuries.
As I remember, one of my 2 teams (I forget which one) used to suffer 15 injuries within 1 week with players out for about 4.5 days in average. The situation should be similar to yours. If this suffering team was my L13 Team, this should be the period in which the no. of red packs dropped significantly. After this injury disaster, I seldom use my red packs on short term injuries.