I have no real friends?

i'm a junior in high school. i have 2 "best friends," but i feel distant from them lately. i was recently in a situation where they left me out, but things have gotten better since i confronted them. but i still feel as if i have no one who i can really confide in. my sisters don't believe that they are really my best friends, and part of me feels the same way. i could make new friends, but it's easier said than done being that i'm pretty shy. i really just need to get through my final year of high school.