From: the Netherlands
I don't think you should worry to much. If your supplies are going down, look at whats eating them. Repairing industry? Flying sorties? Combat? Expanding ports and airfields, building forts?
Reduce the amount of sorties your flying, reduce repairs, reduce expansion , limit port building and fort building and you should be able to balance it all out...
"It happened, therefore it can happen again: this is the core of what we have to say. It can happen, and it can happen everywhere.”
¯ Primo Levi, writer, holocaust survivo