I agree with what the previous folks have said. Try to do something you enjoy (or used to enjoy) for at least fifteen minutes every day. Plan something positive into your day.

With the huge stressors that you have it is not surprising that you are sad. Those are some difficult things to deal with. I am so sorry about the loss of your son.

Perhaps it is time for some tough love for your daughter. My son reached that point two years ago and I wrote a contract and had him sign it. Most important was that he had to respect me or he had to leave.