Can intentionally thinking intrusive thought feel real?

So I had this intrusive thought which felt real. I know most of time intrusive thought feels real. But I had question that why does it feels real. Than I purposely thought the same thought to analyse feeling which come with it. It felt real but I could not understand why. Than I had a thought that " Wait is purposely thinking intrusive thought is intrusive?" Like if I thought a thought intentionally than it should not be intrusive. Even if I thought the intrusive thought from earlier. Than if this intentional thought felt real than does it mean something? Can this mean the thought is actually true?

Please tell me.