What am i supposed to believe???

So right now i am sitting in the Great Hall (that's the really important name they gave the giant unfinished portion of our school building), and i don't know what i am supposed to believe. Some people i really trust told me today that someone else i really trust is (to put it bluntly)a two-faced, people pleasing liar. You know, the type of person that says one thing to your face, but says something totally contrasting to someone else. That encourages you and makes you feel like a friend to your face and makes fun of you to others. The conflict here is I really don't want to believe it. As i said (see above) I really trust this friend...and i am giving them the benefit of the doubt, which will probably be to my detriment, but why would i want to be hurt, if agreeing that they are a two-faced, people-pleasing, lying jerk would still be painful, but less so? You know the old saying, "burn me once its your fault, burn me twice it's mine"? Well, right now i don't know what to do. On one hand i want to sit here and cry and go back to my dorm, turn off my phone, and sleep till next semester, and on the other hand i want to call my friend, and tear them apart, and make them feel 10% of how i feel right now. I could care less about any extenuating circumstances. The fact that i was told that one of my friends is a betraying weasel (not their words) hurts. It hurts because i don't want it to be true. It hurts because it has happened so many times before with so many so called "friends." It hurts because it makes me feel like i deserve that. I know my personality is somewhat flawed in many ways, but do i deserve that?? Why did they even have to lead me on as my friend...why couldn't they have told me off in the first place and spared me all this heartache? To me they don’t seem like that type of friend. O well, i am probably making a big deal about nothing...probably some misunderstanding. By the way, if you're thinking this is about you, you're probably right...and tell me the truth...its the only thing that matters right now.