Hi, there.  I'm sorry this is happening to you, but it's pretty common for a spouse to withdraw when suffering from depression.  Sometimes people feel pretty badly about themselves and think they don't deserve to have anyone love them, so push them away before they get the rejection they feel is coming.  If you look at past questions in this section, you'll see quite a number of people have written in about the same thing and you might find something useful in the responses.  Is your wife in therapy?  If she is, you could ask her if it would be okay for you to come with her to a session to talk about your concerns.  If she isn't, you might suggest that you both see a couples therapist - my husband and I found this to be extremely helpful.  If nothing else, you could find a therapist for yourself so you have some support during this time.

For now, you might just want to give her more space and ask her if there is anything she would like you to do for her to help her out.  Only time will tell if things will get back to "normal" but don't stop living your life.  I know it's hard to enjoy anything when your spouse is like this, but it's important that you get away from it now and then and get some perspective.

I hope this helped some, but feel free to let us know if you have any other questions or just want to talk about what's going on.  I wish you all the best.