Losing your temper with a five-year-old is a fight you already lost by starting.

Losing your temper with a small child is a contest with no possible win. They do not have the equipment to argue at your level, so the volume lands as fear rather than as an argument, and the thing you were trying to correct gets buried under how it felt. You end up teaching the only lesson you did not intend. Being bigger was never in question, which is what makes using it strange.

Step out for thirty seconds if you need to. Come back, get down to their height, and say the same thing quietly.