I have taken prozac in the ast, from memory it tok 4-5 weks to become effective, your wife's doctor may need to increase the dose or change her meds if there is no effect after that time. It worked for me on and off for about 5 years then started to lise effectiveness so I'm now on citralopram
Tiredness, in fact total exhaustion, is very normal with depression I'm afraid
until your wife feels a little better she may find new hobbies, or in fact any hobbies too taxing, at my worst I cant even concentrate on reading (normally I can get through a good book in 2-3 days), I found audio books helped me and watching lighthearted DVD's that were easy to follow too (daft childrens ones a lot of the time like some of the Disney productions) but we are all different. I would suggest not pushing activities and hobbies at this stage or our wife may feel overwhelmed but to suggest and leave it up to her if she wants to do them.
Things that help me are gentle gardening in the sunshine, gentle walking in the sunshine, needlework, painting and drawing, watching birds on the feeders, talking to people who know how depression affects us and occasionally cooking
Your wife is incredibly lucky to have someone who supports her so much
Z xxx