John,
It sounds like you are going through a difficult period, but I sense that you are determined to get better. Prozac may be associated with weight loss, but it seems imperative that you inform your treating physician immediately about your 15 pound weight loss. She may also want to review your thyroid status and medications. Cognitive-behavioral or interpersonal therapy may also be helpful, in combination with antidepressant medications, especially with dealing with the stressful changes that you are going through.
It may sometimes take up to 4 - 6 weeks to feel the full benefits of antidepressant medications such as Prozac.