I understand where you coming from. Depression makes everything seem uninteresting, mundane, downright drag. Seek Him, continue to do so. Knock, and ask... And you shall what again?

It does literally feels like the end of the world. And you feel like you are going nuts, that is very normal. It takes a while to go through it. Remember, it is to get through it, not OVER it as people put it. You will be going thru the emotions like a roller coaster ride. That is called the 5 stages of grieving:

"The five stages, denial, anger, bargaining, depression and acceptance are a part of the framework that makes up our learning to live with the one we lost."

Losing someone we love dearly, whether through divorce, or death, we somewhat experience the same level of stress and despair. Hang in there, and remember to eat, exercise, and be healthy. Doing so helps a lot to balance the sadness and depression.It is tough, the trick is to just do it, like when you go for a run at the gym but really don't feel like it. Just go and do it, and before you know it, it is done.
This site may help a lot, give it a try. You are not alone at all, and all that you are feeling is text book. http://www.marriagebuilders.com/index.html