Stress has a myriad of symptoms, the same goes for anxiety.
It can range from the most common which is rapid heart rate, headaches, muscle tension, "feeling on the edge", fatigue, insomnia, palpitations, perfuse sweating, hot and cold flashes, hyperventilation and lots more.
Psychologically, you may feel that your head is just too crowded with thoughts (and not good ones at that), or irrationality, moodiness, proneto outbursts, etc.