Trust Issues...

I have developed a problem in trusting people just recently. I don't like to trust people because I know that they will make me lose my trust on them soon. I had a bad experience during my first year in college(last year). I trusted my so-called "friends" and eventually, they did something that made me distrust them now. I don't see them much these days but when I do, I always fake a smile and I always hide my true thoughts from them, just because I don't trust them anymore. They are more like companions to me now than friends...