How do I not get so upset?

I keep getting slagged all the time and people think it doesn't offend me but it really does :/ I extremely lack in confidence and my so called friends are making it worse :/ personally I like the colour of my hair oh I'm a red head btw and I get complimented by the hair dressers, I get complimented alot by guys for being 'gorgeous' & 'tidy'.... But my so called mates always slag me :( and some guys do to it really upsets me. My so called mates (Emily Lisa Carrie eleanor...) all slag me for being 'ginger' it really upsets me I cry alot and now won't go out incase people slag me cause I can't handle it :( okay well my so called best mate emily always Slags me and it really upsets me why does she do it? And if someone Slags me about me being 'Ginger' she joins in :( she used to slag my teeth all the time so I used all my Christmas money to get them whitened and I now dye my hair to get her to leave me the **** alone but she still persists to slag me, I can't take it any longer how can I stop getting offended by her and the rest of the immature *****? Emily also got really drunk one time and got taken to hospital and her mum went mental at me and blamed it on me but she nicked the drink off her mum and I got blamed :/ I really can't stand Emily but if I tell her I don't like her I wont have any friends (the girl I really get on with goes around with me and Emily, Emily won't let her speak to me) so how can I not get offended by emily and the others? �And why does Emily and others do it? What is wrong with being a 'Ginger'? Do guy like 'Ginger' girls? Thank you :)