God commanded Joshua, and us, not to be afraid.  That sounds like an impossible instruction to follow.  Like you, Joshua had plenty of reasons to be terrified.  He was stepping into the unfillable shoes of Moses; he was being called on to lead a bunch of cantankerous ex-slaves who didn't want to follow; he was about to wage war against battle-tested troops in fortified cities.  He had reasons for fear.  So do you.  You deal with family struggles, financial struggles, health struggles - you have a thousand reasons to be afraid.  But you have one reason to be strong and courageous: "The Lord your God will be with you wherever you go."  That is reason enough.