is all stress bad for you?

Not at all. We need stress to thrive, excel and enjoy life. This is called positive stress. But even positive stress can become negative if not balanced and managed correctly. Our goal is to aim for a positive-stress phase.
Signs of positive stress
Increased creativity - not only in making or creating things, but also in developing new ways to solve problems or finding better ways of doing things.
Increased productivity at work and on a personal level.
A general feeling of wellbeing, happiness and joy - which is how we should feel. It is our birthright to lead happy, fulfilled lives during our physical sojourn on earth.
An immune system that functions optimally, with an increased resistance to infections and cancer. Even if you're surrounded by people with all kinds of germs, you simply don't become ill. People in remission from cancer come to realise what is important to them in life and experience an inner growth and development, which often leads to physical healing. Even people who eventually die of cancer or other diseases, gain an awareness of the temporary nature of the physical body as opposed to the soul that lives forever. This realisation that the spirit lives on leads to a feeling of inner peace, happiness and well being, which signifies health.

A mild degree of stress and tension is good for us. Feeling stressed and pressurised when completing an assignment, often motivates us to do a good job. Moderate exercising can produce temporary stress on some body systems, but its health benefits are indisputable. It is only when stress is overwhelming, or poorly managed, that its negative effects will manifest.
The goal of dealing with stress is not at all to eliminate it or even reduce it. Stress management and relaxation techniques help you to manage and control your daily stress, to ensure mental, physical and emotional well being.