Who can I trust?

Right i have my 4 best friends and like 2 of them I know dont really say anything personal about me behind my back maybe something like about a sport im not doing right but nothing personal. the other two, well they come to my house on their own and act completely normal fine like im one of their best friends, but one of them always talks about me, in a taking the piss about me n other stuff. then the other one like laughs with him because ive caught him before but he tells me everything the other person says to him about me but like when their together there always really weird like saying things to me on msn or phone like joking around together but saying there being serious but really there having a joke between eachother about me. but basicially that doesnt really bother me but today, 3 of them were together and i thought 1 of them was being snotty but he was on the pc telling the others what to txt to me but i didnt know that so i was like why are u being snotty to me but thinking his replies where him txting me but it was the others typing what he told them to but when he told me this when they had gone i knew they wud of changed what he said a bit on msn but i really got angry at the one who was on the ps3 but i didnt know he was on the ps3 so i got angry over people ****stiring basicially. sorry if u cant follow this. so then like when the other 2 went home they were like what happend between u and kyle and i was like but werent u typing for him? and they kept changing the subject but then later on they started being snotty to me! but i could tell they were doing it on purpose. to the point i do have other friends in school but these are my best friends but i dont know if i can trust any of them anymore and when i say to them like what are you saying about me or whats the joke they end up having a go at me saying im paranoid and get in a mood with me even i catch them red handed! I cant just go to the other friends and leave them its not as simple as that. i rly dunno what to do.