Whether one has a positive outlook, a negative outlook or something in between, you play the hand that you've been dealt.
The decisions that you make, the initiative that you show or fail to show all exist within the context of randomness. You can struggle to exert your will in any situation but you are still nothing but a finite being with limits that are placed upon you, many of which do not reflect choices that you've have made. ( I didn't choose to be born with the tendency toward mental illness. )
If that sounds negative then perhaps that is because it is negative. Life is a never-ending series of variables, frequently negative and not because of any pessimistic attitude. For example, cancer kills the courageous as well as the cowardly. It's not a matter of self pity or defeatism, it's just the world that we live in. Yes, you can struggle against it and shake your fist in proud defiance or you can crumble and fall to pieces, but in the end we are still just stumbling in the dark.
Being an optimistic determined person is in itself a ( random ) gift that enables some of us to rise above critical situations that send others down in flames. Some persons are optimistic because
that is their nature to be. It's much easier to be strong when that is your nature. Believe me I have exhibited extreme durability and determination just by remaining alive. I do not say this lightly, but I suspect that many persons who feel as I do have already made their exit from this life. Don't underestimate my efforts to try and make the best of my situation. I have lived with my "deathwish" for literally decades and I'm still here struggling against it. Many others have thrown in the towel and killed themselves to rid themselves of their pain. For the time being I am still here..living in hell...but I am still here. ( That's more than many can say who have faced similar circumstances. Why ? Because they are already dead. )
PS, I do appreciate your words of encouragement, though and I see that you are simply advocating a proactive approach as opposed to being passive.
You don't seem to put much weight on free will. Many things are decided for us before we are born, or in the duration of our life, that we have no control over. But we also have a choice in other matters, and if your making a choice it can't be random. I'm making the presumption that free will exists here, and that we are not all robots acting acording to the laws of pshysics

I know it isn't as easy for you to be a positive person as it is for some other lucky guy born with the right brain chemistry and structures. But you still have something to say about conditions in your own life. It's important for people that are struggeling in some way or another to realize they have power over their own fate. Some of the power we have lost or it has been stolen from us, but i believe it's not all lost, and that we can reclaim it. Read about learned helplessness on wikipedia http://en.wikipedia.org/wiki/Helplessness%2C_learned. Extract from the text:
Learned helplessness is a psychological condition in which a human or animal has learned to believe that it is helpless. It thinks that it has no control over its situation and that whatever it does is futile. As a result it will stay passive when the situation is unpleasant or harmful and damaging. It is the view that depression results from the perception of a lack of control over the reinforcements in one's life that may result from exposure to uncontrollable negative events.
From http://net-burst.net/hope/helpless.htm:
Learned helplessness is so horrific that experiments have usually been restricted to animals, and even then psychologists felt the need to justify themselves as to why they would be so cruel. In one such study, experimental psychologists designed a dog enclosure, divided by a low barrier and wired to deliver electrical shocks to half the cage. Dogs quickly learned to cross the barrier and avoid the unpleasant shocks. New dogs, however, were given the shocks no matter what they did. The scientists then changed the conditions so that these dogs, like the first ones, could easily avoid the shocks. Yet the dogs never learned to escape the shocks. Being subjected to a no-win situation had rendered this second group of dogs incapable of discovering the simple way to avoid the shocks. Even in their home cages they seemed lethargic and dejected.
It's very easy to succumb to defeatism and negativism. But my point was that these are only mental mechanisms that take our mind off the real truth, and that is that we still control our own fate, to some degree or another. We are not forced to succumb to learned helplessness. Because we understand the mechanisms behind it.
Allthough random events has made you genetically sensitive to mental illness, you don't have to make this something that has absolute control over you whole life. Maybe we should try to see though our mental prisons and see that the brain is just a machine that can be understood. I find great support in rationalizing my problems and trying to see them from the outside.
By the way i'm not trying to prove you wrong or anything. Of course i don't really don't how you feel, and maybe i'm wrong about everything about you. I just find it stimulating to think rationally about the problems we are having. Things get less scary and frustrating when you understand them. Unfortunately you can't think your way out of emotional problems, and our rational brain can't make our emotional brain better. But i think it's better than nothing. Insight removes fear.