ramshah; You recognize the effects of negative thoughts; that's in your favor, many don't, and 'blame' the environment for their problems/troubles.
Where do your negative thoughts come from? We can't see "behind the scenes" but we can infer what's behind the scenes. From who can we learn to do so? From those who are successfully doing so. Scientists, they observed 'matter', the macro level, but could not see sub-atomic/energy that 'makes'causes' matter. Electronic technology demonstratres how well they understand and influence the sub-atomic level.
Our perceptions are not mirror images of the environment (no matter how much they appear to be; we only believe they are). We 'meet' the environment with expectations/evaluations that filter, color what we see the way sun glasses color what we look at and see.
Thoughts are artifacts we use; who 'makes' them? We can't see where they come from or how many are available from the same place. We only see them "on arrival".
( I may not be 'delivering' my understanding cogently enough ,yet, but I'm 'working' on it).
Carpenters, plumbers, etc, work with what they see; electronic 'folks' include what they can't see.