Ok here's an update. Yesterday I had 2 more friendlies, this time my friends arranged it. Guess what - no injuries. My cup game was also injury-free on both sides. I didn't change any settings fom my previous days and now I come to believe that it was just my bad luck to have this long period of injuries.
Whatever the injury-generating factors are, as mentioned in this and other threads, they were not the case in my team. So the only explanation is bad luck/coincidence/game mathematics.
Still, I feel for all of you that are currently experiencing too many injuries. Good luck for all of us