Friend issues everywhere...?

Hi:) I'm in a really tight group of friends. Normally everyones always crazy nice to me, tells me everything and so forth. Anyway te girls in my group are guy obsessive and never want to hang out with other girls and the guys in my group (who I hang out with more because the girls never want to hang with another girl) are my best friends in the whole world. I thought I could trust them with anything. Anyway recently I recently learned they each did something terrible and above that they are holding it above eachothers heads...blackmailing their best friends. I have officially lost all trust in people. Theit sense if humor normally involves making fun if people and normally it's not to bad but recently I feel like it's been terrible. They are ALWYS making fun if me... In done I just I dint know!! Im not sure what to do or who to talk to. Please help me..:'( above this my nana just got put in a home where people live a few days to a few months... I just don't know what to do anymore someone please help me. I never cry and I'm almost in tears...