To dream that you are under stress is a reflection of the stress that you are experiencing in your waking life. Your real life stress that has been carried over into your dream state. Even in your sleep, you may be unable to relax.
The dream may call attention to setbacks, obstacles, self-doubts, criticism that you are facing in some waking situation or relationship. You need to take some time away from whatever is stressing you out, and spend time relaxing and taking care of yourself.