If you work with a good psychologist, you will work on your depression and its causes without medication (although some psychologists have begun getting certified to give medication too). I would pick only someone who specializes in depression.
If you were my patient, there would be a few things I would have to clear up. First, if you lost your true love, you should grieve. Maybe you should grieve for a year. If you want to cut it shorter, grieve more often. Cry and cry some more. Many of us have families who don't believe in crying as the way to heal. Many are in a hurry for the crying to end. Those messages can cause depression. If you are bottled up, taking the cap off will help you/her grieve.
If this is about not having said everything she needed to say, then she should think of ways to talk to him especially about all the things unsaid. Have another funeral, a private one, just her/you and him and cry some more. Then, go to a movie or a concert or volunteer for something.
If that doesn't help her get back into life, then she has "complicated bereavement", which usually is the result of unacknowledged disagreements OR early childhood abandonment issues. THEN, in my opinion, you go to therapy.