Why can't I stop thinking?

This is my typical position now a days. Thinking helps me in a number of ways. After joining this course, I have been doing too much thinking. I think this is what happens when you are serious about finding solutions to the problems. I am able to think so much because I am really not having any constraints. I have been able to think and find solutions to a number of business and personal problems I have encountered in my earlier life. But I have a few problems with this mode.

1. I am not able to implement many of them. Implementation is where fiction becomes reality. While on the paper the idea looks perfect I know there will be tons of implementation challenges and people issues. It is frustrating to realize that I may lose the idea completely.
2. I am not sure if I have enough persuasive skills to convince other parties that my idea can work. I think this is a very difficult task. Sooner than later, I have to develop these skills.
3. I can't turn off myself which is causing insomnia. This is a big problem I am facing now a days.
4. I can't concentrate on what I am currently doing. I am worried about what I should do next without completing the current task.

Having experienced the advantages and disadvantages of this situation. I have come to a conclusion that you need to stop doing in order to start thinking and you need to start doing in order to stop thinking. Have I confused enough? Any comments?

P.S.: I made the above awful picture.