Staying active is a good way to keep your self-esteem up and stay in good health, but being too active can be more harm than good. Excess of anything is a bad thing, or so they say. Living a healthy active lifestyle means that you can keep yourself productive without causing yourself stress. You can go about this by managing your time more efficiently, so that you work as productively as possible. For example, if you are a weightlifter you should take rest days between your workouts to prevent straining your body more than necessary. Your body needs that time to repair itself.
Let us discuss what you should do overwork yourself. First, you are going to want to figure out what caused your injury. Second, you are going to want to refrain from that exercise or activity, and not only refrain from that particular exercise; but, any activity that may work the same sets of muscles in the injured area. Third, you must allow yourself adequate time to recover from the injury. The worst thing you could do is start to work the same muscle group again without allowing adequate time for a full recovery. Work smart not hard.