I spent about six weeks in the beginner class before I moved to the basics class. And, like you, I didn't know what I was doing and was quite embarassed. Still am, occasionally, when Sensei shows a technique I haven't seen before. It is hard not to worry about it, but we have all been there. The whole point of the Basics class is so that you can learn the basics, after all.
As for extra practice time, I usually show up before class or stay after class and ask a senior if I have a question. Often, even if I am working with someone at my skill level, a senior will come over and make helpful suggestions, which is great. Again, I know it's hard, but if you ask you will find people more than willing to help.