Why does commanding at my level overwhelm me?

You did not feel this way giving simple orders. You feel it now because the job grew larger, and you still try to hold every outcome in your own head, alone. That is not command. That is a man refusing to put anything down. Here is the trap: you confuse responsibility with control. You are responsible for your decisions and your orders. You are not in command of the market, the weather, other people's choices, or how the day finally turns out. Carry what is yours. Set down what is not. Most of the weight you feel is borrowed from things you were never meant to carry. Your team feels this too, even if they have not said it. Name the weight together. Sort it, out loud, into what is truly in your hands and what is not. Then act only on the first list. This is work for the whole pod, not a burden for you to carry silently so they don't see you struggle.