It seems that a lot of people with anxiety (or depression) have trouble getting their parents to understand that it's something that needs professional help and not something they should/can just get over.
good luck with driving though. Just driving where I live in Indiana sucks, I'm terrified of driving to Kalamazoo in January to visit my boyfriends family. It's definitely not a great time to take a road test.
Do you know how to handle icy roads? Maybe try practicing in a big empty parking lot with someone who does. My dad taught me how to do all sorts of stuff like hand brake turns that way, as well as basic ice handling. You'll feel a lot better about driving in the winter when you have that practice under your belt instead of finding out on top of a bridge like you did today.
Driving will get easier and less stressful the more you do it. I was horribly nervous when I first started but now it's the easiest thing ever. (Except for rain, I had a traumatizing accident involving rain)
Spend more time practicing behind the wheel. Eventually it will be second nature. I wouldn't rush getting your license and then end up getting hurt.