Welcome Heisenberg.
It's obvious you have a healthy uncertainty ;)
What is truth? In the last sentence you made (IMHO) a wise observation towards realizing truth by seeing what it is not: “Don’t believe everything you think. The brain is just as treacherous as the heart.” The rest of your post was just the “treacherous” play of thoughts, beliefs and emotions. Do you see that?
Forgive me if I am wrong, but I would interpret what you are saying as: we will not find truth in thoughts and emotions. The reason for this is that we can simply not find a stable foundational TRUTH in the ever-changing turmoil of mental and emotional activity. Which is why we have kept asking the same questions and getting nowhere throughout our history.
So, perhaps, the remaining question is: is there that which is still and unchanging?