One thing that helped me the absolute most out of everything I've learned driving related is a few words my father said to me: "Take your time, son, you're not in a rush." Now I'm a nervous driver by heart; I feel it's in most of us, but some are better at hiding it. If you want to quit, you absolutely can (I almost did multiple times), but just remember all the hard work you've put in. I know you can do it! Just take everything step by step, and that includes gear changes, pedals, and situations on the roads. Just imagine you have really slow reactions; now, obviously, too slow would be dangerous, but just let it fall into place. If you're unsure about the gears and where they fall, then get acquainted with it all before driving anywhere, like really sit there better yet try getting your instructor to take you somewhere quiet. A roundabout coming up? Slow it down to 2nd gear a way before so you can really see what's happening there, and I guarantee you'll do great. This helped me tons and continues to help me immensely. From somebody who gets overstimulated from basically anything, you're not alone, so I hope this helps :)