How do I stop being squeamish?

Now I don't know how old you are, but there is no time like the present to overcome this, the other answerer is right about Desensitising yourself. The trick is to eliminate all emotion from yourself while watching clips, and make sure that they are very graphic, for a little while you might get sick, or not feel well, but eventually you will feel nothing, and that is when you know that you are no longer going to get squeamish. You do not have to enjoy it while you watch, because that isn't your aim, all you need is that little voice in your head telling to to stop it, to go away.