Stress and anxiety can both bring muscle tension, poor sleep, irritability, stomach discomfort, a fast heartbeat, and difficulty concentrating. Looking at symptoms alone rarely produces a clean answer.
A more useful starting point is context.
The National Institute of Mental Health describes stress as a physical or mental response to an external cause, while anxiety can continue even when there is no current threat. This is a helpful distinction, but real life is less tidy. A difficult workload can generate anxiety. Ongoing anxiety can make an ordinary workload feel unmanageable. Health conditions, medication, caffeine, sleep loss, trauma, and depression can also shape the experience.
The question is therefore not "Which label can I prove?" It is:
What seems to be maintaining this experience, and what response is worth trying next?
You can think of load and alarm as two dials rather than two separate boxes.
There is usually something concrete to carry: deadlines, conflict, caregiving, financial strain, uncertain employment, too many decisions, illness, or too little recovery. Attention is pulled towards unfinished demands.
For example, Mara has three urgent projects, slept five hours, and has skipped lunch. Her shoulders are tight and she cannot focus. When one deadline is moved and she eats, the intensity decreases. Load appears to be a major part of the picture.