I think all have this problem in the begining,just be patient.In 1-st few season this was big problem for me too,i was angry many times but when you build your stadium this is not big problem.Injuries is a part of the game but in hight lvl when you have medical on max lvl its 7 red packs evry 4 days+1 from gift freinds and + some when you have fairplay its 49+28+smt like 15-20 per season=near 100 per 1 season its enough to keep importnant players for almost all season