Why is my body shutting down today?

I have been under tremendous stress lately due to the combination of suffering 2 miscarriages in 3 months, my marriage hitting a rocky patch and "breaking-up" with my best friend. As a result I decided to get my life back on track and make some changes to better myself. So this week I started exercising every day and eating about 75% better than usual. I have been doing this for 4 days.

Then today, I woke up and am almost unable to function. I am so tired that not even 3 cups of coffee and a red bull were able to give me even an ounce of energy. Just changing my toddler's diapers feels like a chore today. I had a good night's sleep and cannot figure out why I am feeling this way.

Is it just the stress or is it possible that making too many positive lifestyle changes all at once can make your body shut down??