welcome speed_freak..
believe it or not, i can relate. my drug of choice was methamphetamine, which induces feelings similar to the adrenaline rush, a dopamergenic response. in our heads, perhaps its the same addiction. in our lives, we may have taken different actions to produce the desired effect, but your problem sounds very similar to mine. my life got super super boring when i didnt have my speed; i became totally obsessed with the feeling.
the problem is not with your driving, it's with your thinking. you certainly can use the 12 steps of acoholics anonymous, or any other 12 step group (A.A. was the first so i find their steps and books to be the most helpful to me, even though alcohol was not something i obsessed over)..- and in hopes of removing the obsession that may end up destroying your life. i suggest going to an AA meeting just to observe and pick up a Big Book-- you may be able to relate and modify their steps-- everytime they say "drink"-- you should think "drive"... taking these steps may end up saving your life.
of course, you will probably have to try some more controlled driving, and you will find it difficult as anyone would to abstain from driving, but perhaps that may be neccessary for a short while. if you are unsure that you are a speed addict, try some controlled driving. if you find that you cannot control your speed, perhaps a little driving abstinence is in order.
welcome, once again..