At 46, I've definitely had my share of ups & downs and can be cynical at times (especially about religion and people), but overall I feel very positive about life.
I would like to share with you a few things that you can do that are relatively inexpensive and I'm almost 100% sure will help you for the rest of your life. Give it a try. Start doing this in by December and you will thank me by 2007. This is no joke.
1) Go to a dog shelter and bring a dog home. I have a German Shepard. I highly recommend this breed. Find a puppy if possible. Get a book on how to train him/her. I never had a dog until my forties. You will bond with this animal like you never thought possible.
2) Get a Topo map of your state from the bookstore and locate hiking trails within an hour of your house.
3) Get yourself over to REI and buy yourself a decent pair of hiking boots.
4) GET YOURSELF AND THE DOG INTO THE WOODS! The combination of nature, solitude, the dog, and beautiful scenery is unbeatable. Spend enough time there and you will start to notice things that most people don't. You will also want to come back time and time again with your new friend. This one step alone can put you mind back on track with or without the dog.
5) I don't know if you exercise, but for me it's an absolute requirement to having a good life. Started at 10 and never stopped. At the very minimum, walk the dog in the hood for at least 30 min. every day. Preferably, include some form of weight lifting and maybe purchase a stairmaster or treadmill. The science is there that this increases positive moods.
6) Drop some of the red meat out of your meals and replace them slowly over time with fruit & vegetables.
7) This is an advanced step after your mind is back on track: FlyFishing at remote mountain lakes (or rivers for some) can take your mind to a place that at least for me, is not possible anywhere else. After FlyFishing at places like below, you'll never want to turn 85 for fear of never being able to return.
I hope the above helps you.