You've done so well in learning to be negative, that you need to take that same technique to be positive. You mentioned that you see negativity in almost anything. I think what you need to do is analyze when you do that and ask yourself why you do that. Then you need to try to find the positive in it instead. For example, if you hurt yourself while riding a bike, you could be negative about it, or you could say " Hey, well at least I didn't break anything."What I like to do when I'm feeling negative is to go out and into nature and just see how beautiful it is. Beauty and happiness and positivity is all around you, but you have to change your perception in order to see it.