I am sorry to to hear of your suffering. If there is something physically active you can do out in nature that brings you pleasure, it can help to refocus your mind away from the cycle of thoughts in your mind. If you can catch your mind going down the negative thought path before you are overtaken by it, you can circumvent it. Try closing your eyes and envisioning where your hands are in space in front of you. Focus intensely on your physical body and the location of where they are in space. There will be a sensation of a warm, buzzing feeling. Focus on it and hold that feeling as long as possible. Soon you will realize you are no longer thinking of the thoughts which are depressing you. It's a start.