Dont know what to do?

basically all my friends are like this they can be good mates at times and at other times just make fun out of you till you feel so angry close to punching them sometimes it just puts me down cos the thing is noone else gets picked on like i do i could just be sitting there and someone would poke fun at me in an arguement i never have anyone to back me up and the most annoying things that really grinds on my nerves is when they come to talking about how they hate the piss taking out of them yet in about a few days theyll start taking the piss again. Hell one of them dbagged me and says sorry then goes on to take the piss out of me bragging to his other mates so they can all laugh at me(I will have revenge i dont care hes taking it too far he has it coming to him) I know i should just find a new group of friends but the things is if i were to leave that group i wouldnt really fit in with any other groups making me a loner so what should i do. pls help