Bullying problem please help.?

right, im in year 9 atm, going into year 10, and i've been being bullied now for well over a year, by a big group of girls on the other side of the year [we have 2 sides], altogether around 20-30. but its just about 5-10 of them are the main ones. i've been physically bullied and mentally bullied. and its come to the point where i cant take it no more! i've been to teachers over and over, but all they say is the 'dont do it again' sorta thing, and theyve done that like 5/6 times, and has it helped no. basically its because i went out with this boy and still am, and supposily i've stopped them all from being mates! other than that its people making up things and telling them that supposily i've been saying i've wanted to 'beat them up' and been calling them stuff, just to give them an excuse to come and have a go at me/physically bully me but my boyfriend is amazing and has stuck up for me, and helped me all the way through it, love him for it. so its the whole making up romours, dirty looks, writing all over my school books, coming and having a go, shouting out things, throwing things, basically the whole lot of bullying. keep in mind i've had all of this for over a year, and none of my mates have helped me, only my amazing boyfriend, all the way through. like i said its come to the point, where i cant take it no more! i will add details, if i think of anything else, because i might have forgotten something so keep checking and replying! i need help ... what should be my next step of action ... higher up the school, such as dep head, or headteacher or anywhere else. please please help. ive put it in womens health because i would preferable like women to help me, and plus its partly about me a girl and my health so yeah thanks for any help, xx