This is for both of you and everyone in general......Why don't you just try taking these grandiose ideas and breaking them down into really small, more attainable goals? It will help you to aknowledge the fact that you have these aspirations, and also organize them into a reasonable way to acheive them, and give you the sense that you are actually making progress.
You'd have to do it in a way that best fit your specific goals, but say you want to write a book on some major physics breakthrough. You could start by trying to fill a small notepad sized sheet (like 3 by 5) of an idea every day, just a second every day to jot down a thought. Just jot down an idea or two, and once you have a lot of these little notepad sheets, start organizing them into categories. Once they are into categories, and you have enough, take a category and write a page. Once you have a few pages, start organizing the pages into a chapter. Etc....
With such a broad goal, it's really easy for anyone to get overwhelmed. If you purposely break it up into tiny little goals that you can accomplish every day, it might really help.
Of course, getting treatment for whatever may be holding you back wouldn't hurt either (if, Dorgus, it turns out that you do suffer from bipolar)