I'm emotionally wrecked and I'm feeling so depressed that I don't!

I'm a sophomore this year and I must say it has not been going well as I planned and hoped for. I'm a shy girl and I'm usually quiet. Sometimes it's hard for me communicate with people.
Last year when I was a freshman it was pretty good. Everybody seemed okay and freshman year was pretty easy I must say. Now this year, subjects become even more harder and the friends I've had in the beginning of high school seem to fade away. Like my close friends seem to act differently as though they want to look cooler this year and they even changed their attitude a bit. Now I kinda lost them as friends. As of now I'm stuck with a group of black people and the worst part, is that I'm the only asian. It's so uncomfortable for me.... today my black friend (girl) noticed that I was the only asian and she said that it was pretty cool how I'm the only asian and etc... I didn't even bother to listen to what else she was saying cause I was not feeling the same way. Like seriously how would she feel if she was the only black girl hanging out with asians and they were doing asian related stuff, I'm pretty sure she would feel uncomfortable the way I'm feeling around her and her black friends.

So that's only my 1st problem.... my 2nd problem is that in high school, 1st semester has already ended and I got high scores on my subjects. Now it's 2nd semester and my courses for this year are: History, Vocals, Computer Tech and English.

I HATEEEE Vocals and Computer Tech! Like I seriously regret taking those courses and now there's no going back to change it or doing anything about.

1st of all I am not a good singer and almost all my classmates in vocals class are great singers and have experience. I feel so out of place in that course. :'(
What's even worse is that today in Vocals class we had to sing individually to see how low and how high your voice can go. First it started off as low and then a high pitch. But my teacher would let us stop if we weren't able sing that high. Like she wouldn't pressure us to go any higher.
But when it came to be my turn to sing individually in front of the class I completely failed. :'(
I have this phobia of speaking/singing in front of people and my voice was so low they couldn't probably hear me and I was so nervous. They didn't laugh but I could tell that they felt bad for me. AND I HATED THAT FEELING. It was the worst feeling I've ever felt.I completely embarrassed myself. I can't sing and I'm stuck with that course.

Now for Computer Tech, I'd have to say that course is pretty darn hard. It's not a really easy course to pass.
I am not even interested with computers and I definitely do not know a whole lot about computers and the worst part, is I'm the ONLY GIRL in my class. YES, the rest of them are all guys.
It freaking sucks... I have no one to lean on to and be partners with whenever my teacher assigns partners. It gets really lonely and at times I force myself to read a book. Whenever I get too lonely in class, I cry but I don't let the tears fall.

I can't change those 2 courses because those are the only courses available.
And now I'm stuck with them till June.
I did so well in 1st semester that I got an 80% as my average mark.
and I was hoping to get an 80% as well for 2nd semester but it seems impossible. :(

If I get an 80% for both semesters, I get to be on the honor roll at my school and that has been my goal since freshman year. During freshman year last year I didn't get an honor roll.

Ugh I was thinking about all these problems at school and I completely broke down after school and went to the washroom and sat on an empty stall. I cried.

When I came home I cried even more.
Ugh now I have this stupid computer project that I don't even know how to complete. It's so hard to understand.
But thankfully my black friend will help me with it. I asked my sister to help me but she refused as always. She's usually the unhelpful, lazy, stubborn *****. She never helps me whenever I don't understand something at school and she's freaking smarter than I am.

Anyway I really hate high school. I just wish I died so I wouldn't have to go through depression and pain every single day. It would be nice to feel happy for once.... thats what I've always wanted. :(

Well I'm hoping to hear some great advice. I don't talk to anyone else with my problems except myself. :( Ok thanks for taking the time to read all this, I understand it was pretty long, sorry about that.