I feel like the only person I can trust is myself...Anyone else feel this way?

Maybe I am just hanging out with the wrong crowd, but for the most part, I don't trust any of my friends and so I have a hard time becoming really close with them. For instance, I'm in a sorority and living with 6 of my sorority sisters and one of them was complaining about how she can't stand this other "friend" of ours because she is controlling, always has to have her way, and rude. Well then a day or so later I overhear her telling that same girl that she considered her one of her "best friends". I also had kind of a similar experience in high school...but not as bad. I just really have a hard time trusting people because they say one thing then turn around and contradict it. I can honestly say the only person I can trust in this world is my mom. I even have a sister that's a year older than me and while I could probably trust her I don't get along with her because of the way she acts and how she treats my parents with disrespect. Anyways, I am just wondering if something is wrong with me, or if anyone else feels they can't trust anyone. I hate not being able to trust anyone...I feel so alone and excluded in the world it's a terrible feeling!