UK Islamist Leader: Islam Will Dominate America

Am I Islamophobic for believing what people tell me? If a person says they are going to kill me and I see no evidence that they have the means of doing so, I laugh at them. But, if a person tells me that they are going to make me submit to Sharia and I see evidence that they are gaining in power (numbers) while non-Muslims are refusing to resist their threats, I begin to worry that they will make good on that threat. Does that make me Islamophobic?