To be afraid of thoughts is like being afraid of ghosts. But thoughts exist and ghosts don’t. Thoughts are real but ghosts are not. Ghosts exist only as beliefs, or thoughts. Well, in that sense ghosts are real.
The mind made self, the ego, the idea of who you are, is also real, but it is made of thoughts. It is like a ghost, a spirit. Without your thoughts about yourself you are nobody. It is different with the sense perceptions. They are also processed in the brain, but that is not something "you" do. That is something the brain does for you. You can see with your eyes and hear with your ears, you can feel the wind in your face and smell the horse dung from a distance.
What are thoughts made of? Are they made of electricity? Are they made of light? Are they made of chemicals? It doesn't really matter. Thoughts are sometimes interesting, yes but mostly quite annoying. It is better to ignore them. It is better to leave them alone. Treat them like you treat the drunkards at a train station.
But who is this you who treat the thoughts as drunkards? Isn't this "you" also made of something, chemicals or electricity or whatever? Yes, but you didn't create it. The brain creates it for you.
What is waking up in the morning after good nights sleep and what is passing out at night? What is panicking? What is stressed out? What exactly is experiencing peace beyond understanding?