Positive Psychology = Happiness?

I’m a type of person who would like to have a positive psychology and I try really hard to look at a situation in a positive way. However, there comes a time when it becomes strikingly hard to look at my own not-so-good situation believing that there will be a silver lining beyond my murky clouds. Is positive psychology something that we can all learn and apply to our lives? Or rather, will positive thinking bring more happiness in our lives? I mean, some people are genetically gifted to overlook the negative sides and exponentially multiply the good sides to their situation. On the other hand, some other people are naturally bound to sink themselves into pessimism and tumble in their own Heathcliff-ego. I guess my question is, how happy can we get?
I once took a course about happiness and came to know a book called Authentic Happiness by Martin Seligman. In this book, Dr. Seligman set up an interesting formula about happiness, which is H= S+C+V. In translation, happiness equals the sum of an individual’s set range (S), circumstances of one’s life (C) and factors under one’s voluntary control (V). The set range claims that there is a set range of positive or negative emotion one can feel depending on their genetic makeup. Boom! Well, one of my assumptions is correct according to Dr. Seligman. Next, Dr. Seligman proposes that circumstances are something that is expensive and rather impossible to change and I do agree with that note as well. You can hate your job thoroughly, but sometimes you just have to stick to it. The most important part of this formula is V, voluntary control. Dr. Seligman strongly suggests working with V which is about all you can do to personally increase your happiness level. How to increase your V level? Forget the past, focus on the future, forgive and be thankful! Easy said then done. I have been thinking about this formula for quite a while. But, honestly, would this formula really come into our minds when we are in the deepest pit of sadness or floating in the height of euphoria? I feel like this formula itself limits my optimism. I want to believe that I can be as happy as I want and even aggrandize my happiness despite whatever genetic makeup that I have. Perhaps what everyone wants to believe is the formula, happiness=me. We all want to believe that we can create our own happiness in our lives and that it will come to us very soon. And if positive thinking really increases our levels of happiness, I have to say I am going to follow my own formula despite how insensible it may sound scientifically because that is my way of positive thinking.