Intensive exercise may circulate the blood to the brain and constrict the optic nerves. If the condition occurs occasionally, just have a rest and reduce the intensive. But if it is persistently or usually, you'd better to see the doctor. Because neurologic diseases, damage of eye rim and eye muscles fatigue might cause double vision.
Well, looks like you really want to lead a healthy life. And it seems that you have taken excessive physical exercises recently. Sometimes our body also needs rest and recovery. Perhaps it is rightly because of over exercise that you have got double vision. So, my advice for you is to take some time to rest and do not exercise everyday, maybe 5 times a week is enough. Maybe in this way, your body will be much more healthy. If the situation remains the same, you should go to see a doctor.