I am so sorry your wife has depression. I am just so glad she talked to her parents. Working the hours she was working she was bound to have a meltdown. The pressure on her must have been tremendous.
Now you are the perfect husband as you can juggle many things as once which may have made her feel guilty for being weak.
People with depression beat themselves up all the time for not being strong enough, good enough and not knowing where to turn.
I would let her know in a short card that you are there for her and not going anywhere. Tell her you support her and that you love her. But give her some space. Let her get through some therapy and let her meds start working. They usually take 4-6 weeks.
Most of all if your with her and she starts to cry please don't say "Now what is wrong?". If she knew what was wrong she would fix it.
I will say prayers for both of you and know she is ill as depression is a mental health disorder. Many people lead normal lives with therapy and help. I feel she will get better.