Its difficult to change yourself.. and normally nothing you can achieve in a very limited amount of time - we are speaking more of years ;-). For now I would make an evaluation what you have and what is left that you would need to "sell" your phD as a success. You are in your final year so you should have at least some vague/general idea of your topic and where you want to contribute (a detailed plan would be better, but lets just assume worst case ;-)).
Start to structure your thesis - you have to write it anyway in the end. What has absolutely to go in, what does not make sense, where is improvement needed? Then have a talk with your supervisor if he sees things the same way or has other suggestions - he is your anchor that pulls you back if you start losing yourself in details. Try to figure out a roadmap together for your last year and define what you absolutely need to achieve.
What I experienced over the years is that if I have no plan, I tend to dip into the fields, read here and there, have this idea and that and get nothing done in the end (opposite of you, you dive into it too deep and get "nothing" done ;-)). With a plan, I can work structured towards a goal.
Hope that helps!