Worried About Our Oldest

I'm worried about my oldest because she is so timid. It affects her schooling the most. She spends at least one night a week crying and worried over something going on at school (usually a homework assignment she had a problem with but lately it's been the end of the year field trips too). This week it was two nights - last night and again two nights ago. For homework, she is always afraid she is going to get into trouble usually because she couldn't figure out her homework but sometimes it's because she forgot something at school she needed for homework. I'm worried about how she is going to handle junior high in a few months. How is she going to handle six different teachers/classes and all the rushing in between each class to get from one place to another when she is a nervous wreck now over one teacher?

She also lets her best friend boss her around. That irritates me because some of the things she's being bossy about isn't what is best for my child to do. Right now, it has to do more with boys but in a couple of years, it will be cigarettes, alcohol, and sex. I don't know if she will be able to handle the peer pressure.

She's such an overly sensitive kid. She cries every time her friends do (and lately that's been a lot from one particular friend). She cares about people's feelings and animals and everything she should care about. I just wish she wasn't such a nervous wreck emotionally.