I didn't have that particular problem, however in the past I have had to deal with anxiety. You will have to gradually face your fear - and it seems like you're already doing this. You can do things to make yourself more comfortable, like having someone who you trust in the car with you, or putting calm music on in the background, etc., but in the end you will need to be able to let go over any "comfort items" as well, as you won't always be able to have them with you...However, I did say gradually, so at first make it as comfortable as you like - do you feel more comfortable driving in the country, or just a short distance from your house? Well then start there, and just slowly extend on it, and slowly you will gain in confidence, and you will be able to drive for a certainty.
You can also see the positive side of your situation - because you have so much anxiety you won't be taking risks, and thus you are more likely to become a safe driver.
Just remember to look back in a year from now, because you will see how much you have progressed, and that will give you a good boost of encouragement as well.
All the best with learning to drive!