You're not out of your mind. I think it is normal to play out scenerios or have conversations with yourself in your mind. That's just thinking as long as you know it is you. Be aware of your experiences though, don't make them create unreasonable patterns in your mind but, don't let them be shaped by your beliefs either. Just be aware.

Now that you're aware of these thoughts you mentioned and how they effect you, you can work on changing your thoughts, start asking yourself questions when you have self defeating thoughts, follow a logical path in your mind and develop a more realistic perception based on that rationality. If it helps, think about what you would say to a friend dealing with this. Is that what you're doing to yourself?

When you catch yourself in those habits, acknowledge and move on to something else if you can't get into questioning it, start thinking about lunch, or your favorite tv show, book, pet, friends or family, whatever. Remember where you are and what you're doing and accept it as it is.

I used to think so negatively and just get stuck on things because that is how I felt then, I started to be more rational about the world. Emotions can't drive a person crazy! I'm smart so, why not use my brain rather than senses to figure things out? I think emotions are just a survival thing. Find for a quick reaction and to gather impressions about things but, shouldn't be used to run your life. When you're stuck in negativity you're feeding negative emotions.