I am very much an introverted person myself. Facebook is very ill suited to people like me. Its too much like real life. Its hard to fit in. Way too much gossip and BS and smalltalk going on.
In my experience, if you feel ill at ease with the kind of people who frequent facebook, getting to know people is a lot easier if you try through forum sites such as this one. Perhaps one on one communication is more your thing rather than trying to fit into a group or clan or clique.