I know we cannot diagnose but that sounds like OCD. I have suffered from OCD since I was a young child. I have thoughts, sentences,words, etc. that go over in my head like a record player for hours. I also will hear a word a repeatedly type with my fingers like I am at a computer. When my anxiety is high it can become extreme and go on for days. My therapist, who also suffers from OCD, says it is an OCD trait. I know what you are going thru, it can be debilitating at times. The advice my therapist gave me is say you have a word in your head that keeps repeating. He told me to say it out loud over and over again until it is no longer an issue. You have worn out the word in your brain, and the anxiety attached to the word goes away. I haven't tried it yet. I've been dealing with this for so long that I've become accustomed to it and just ignore it, but I won't lie there are days when I want to scream and say stop at the top of my lungs. Go talk to your doctor there are medications that can help but I have found that CBT has helped me with the major OCD issues that made my life unbearable. Hope I was able to help. If you have anymore questions feel free to ask me.