Is OCD a protective measure taken by the brain because we react so heavily to our thoughts? So it is actually trying to bring the thought to the forefront of our mind to keep us safe.

Yes it is. It's our body falsely perceiving a normal situation as a threat, and making ua react as if we were in physical danger. Eventhough everyhting is fine. It's like looking at a picture of a lion and freaking out bc you think you're gonna die, Eventhough everything is fine.