How do I stop feeling overwhelmed by scheduling billing and phones?

The phone rings while you are billing while three people wait to be scheduled. Of course it overwhelms you. You are being pulled in three directions at once, and each one feels urgent. That is not you failing. That is a genuinely hard job. The overwhelm eases when you stop trying to do all three in the same breath. Give each task its moment, even if the moment is short. The phone can go to a message. The billing can pause. The person in front of you gets your attention first. Pick an order for when everything hits at once and stick to it. Person present, then phone, then paperwork, or whatever fits your desk. Having a rule means you stop deciding in a panic. You just follow the plan, one task at a time, until the wave passes.