Islam is a religion. You don't have to be afraid of Islam or any other religion. Why would you be afraid of a religion? It is like saying you are afraid of Christianity. That is nonsense/unreasonable. A religion alone is not dangerous. Extremities can be.
But ISIS is an extremity and a terrorist group. There is a reason to be afraid of them, but I am not afraid of them at all.
If they come to my country and blow everything up, then they just do that. There is nothing I can do against them. Okay, this is an exaggeration. They certainly won't do that. But they can certainly blow stuff up and kill people. But I am still not afraid of them or anything else. It is like I go out for a walk, a car (for example a drunk driver) can hit me anytime. Crazy people can attack and kill me anytime. Even the lightning can strike me anytime (typically during a thunderstorm). There is nothing I can do against any of these, but I am not in fear. They can't frighten me. No one can frighten me. Don't let them frighten you! Don't let anyone frighten you! Don't live your life in fear!
Honestly, I don't see any reason why you should fear Islam. It's generally a very peaceful religion and in my experience Muslims are extremely peaceful and kind hearted people, more so than Christians are. Now what you should be afraid of is how certain people interpret the teachings of Islam and the holy Qur'an. There's a reason why even amongst the Muslims they are divided and some people believe in peace while others become radicalised and that's because of how differently people interpret their teachings.
Isis is a complete different ball game entirely, they're one of the reasons why being a Muslim is difficult these days. They are a radicalised group of Muslims who follow Sunni Muslim doctrines. They're just a bunch of Islamist thugs who feel that it's either their way or the high way.
Personally I don't think they should be feared, nobody should be afraid of bullies, but when they're more than willing to shoot you in the face or separate your head from your body then by all means fear them. Fear them because they aren't afraid to kill their own Islamic brothers and sisters, fear them because they truly believe their oath is a righteous one so they don't fear death.
Most of all, fear them because they spread a message that's seductive to the ears of certain Muslims and they can radicalise just about anyone who's foolish enough to listen to what they have to say. They create killers and mass murderers by just talking on the internet or on a radio, if that doesn't make you afraid then congratulations you're a brave person, as for me, it terrifies me.
I hope this helps.