Are you using tactics from this forum?
If so, it happens because most of them are high pressing, extremely attacking with insanely aggressive OI. They rely on outscoring the opposition in all circumstances. It's all fine until your striker(s) get out of form and you start missing all those CCCs, and on top of that in FMC you don't have OI which hugely amplify aggression in these tactics.
The solution is to use tactics which don't require OI and those which don't use Attacking or Overload all the time.