When was the last time you did exercise?
You wake up in the morning, you go to work in your car, stay in your air conditioned office and after work, you go back home in your car. You do this every day and on weekends you visit friends and have fun without exercise. You are killing yourself gently.
Make sure you engage in exercise. It keeps your brain alert and your body fit to enjoy your success. Try doing exercise once a week for a start for 30-50 minutes. You could jog round your neighbourhood early in the morning and I promise you that it will be fun.
Don't be lazy and stop saying there is no time, I told you before to create time for yourself.
Exercise is good for the body, don't be left behind. I do 90-100 push ups every morning before going to class.