Break your project up into chunks or milestones. Work towards each milestone and it will make the project seem not so big and overwhelming.

If you're problem is you spend too much time planning then you'll get faster at this as you do more coding. You'll encounter problems and solve them you'll be able to get through them a lot faster the next time you have the same problem.

You say your mind goes blank when it comes to actually writing code? Is this because you don't know the syntax, functions, etc or is it because you don't know how to do what you want to do? If it is the former, then do some more reading and learning about the language. If it is the later, try thinking about how to do it not in the language but in simple terms. Work through the steps to achieve what you want. Once you have that solved, turn it into code.

As you work more and more with the code you'll be able to start thinking in code. I do this all the time. I find it easier to thinking in code than in other terms. Don't have to convert it over to code. It's already there. Hehe. Thinking like this isn't always the best though.

Also it sounds like you have a lack of motivation. With this you'll need to find a project that interests you and you want to complete it. Motivation to work on a project is something you'll have to figure out yourself. Not much can help you in this area.

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Eric