I need some advice, please help me!?

I tryed to read all of it , but what i see here is your confidence levels are not to good you need to build a steady relationship up with your family, like asking them questions about there day and each day doing this brings your confidence up and try talking to people who you wouldnt usually talk to , this crazy girl your talking about might just be having it bad at home so they feel thats a the easy way to get through the day by taking it out on people at school, this might sound over the top but why dont you try talking to her like asking if she would come to get something for lunch but make it so it doesnt look liek your just doing it , it needs to just look like it is obvious would happen. or your could turn a blind eye to her and ignore her if no ones standing up against her then shes obviously mean but she might be being nasty because shes got no friends or even had a bad 2 years like you and was bullied. you say you cant handle stress pretty much but every day you live you get stronger if people call you names then just ignore it words cant kill you but they can mess with your head so just ignore them or shout one back . hope this helps in some way