First, chill out. Struggling with science or math is not the end of the world. It may feel like you’re the only one who doesn’t get it, but you shouldn’t feel so ashamed of yourself. You’re doing the best you can with what you are given. Just accept the help that is offered to you and don’t feel embarrassed for needing it. Each and every one of the seemingly perfect people around you will one day find something that makes them feel just as confused and lost as you feel in pre-algebra. Most importantly, you’ll learn how to teach yourself things in the way that is best for you, which will be immeasurably helpful once high school and college come around.
Second, don’t care so much about people who judge you because you’re different. At some point in your life, it really is going to be a virtue to be different from everyone else. Middle school is a time when everyone is desperate to fit in, and you will have some trouble finding your “clique.” The way to solve this is not by trying to convince your parents to buy you the purses or shoes that the other girls have. Don't feel bad about the fact that you don't know what all trends are. The reason that you don't fit in well with those girls is not because you have crooked teeth or don't wear makeup to school. You'll hear people say this so many times on TV and in books and think that it's just a stupid cliché, but it really is true that physical appearance is not the most important part of a person.
Next, don't feel ashamed of your interests. People may say you're a nerd, but I am here to tell you that being a nerd is in no way a bad thing. Their approval is not what you should be striving for right now. Don’t try to change who you are just to make them like you. Keep watching your science fiction shows and classic movies, read in your spare time, and do as much art as you want. The world needs more people like you and, eventually, you will meet people who share your interests and connect with your personality. It feels like you're the only person in the entire school who enjoys the things that you enjoy, but don't let that stop you. SPOILER ALERT: it doesn't, and I am so immensely proud of you because of that.
Lastly, I want you to know that the best times of your life are ahead of you. Even though you may feel like an outcast now, you will come to realize that being surrounded by people who think they're better than you is not what friendship is supposed to be. You'll instead find people who accept you for who you are and who you can be completely yourself with. The times with them will be the best ones of your life. You'll be motivated to strive to do the best you can in school. Your confidence will grow. You will become more willing to put yourself out there, and you will be rewarded.
So here’s to you. Keep up the good work. And trust me, it gets better.