You did the most helpful thing you could: You let your friend know you cared just by going to see her. She didn't need a long lecture or an hour's worth of meaningless chatter; she just needed to know you cared.
Often, in fact, the best thing we can do for someone who's hurting is to be a good listener. Do you remember Job in the Old Testament? He lost everything - his wealth, his children, his health, even the respect of his wife. But when three of his friends heard about it, the Bible says, "They set out from their homes and met together by agreement to go and sympathize with him and comfort him" (Job 2:11).
And once they arrived, "They sat on the ground with him for seven days and seven nights. No one said a word to him" (Job 2:13). Later, they would speak and try to help him - but not at first. Rushing in to give advice, or claiming we know how someone feels when we honestly can't, may only make the person hurt more.
At the same time, don't hesitate to point your friend to the hope we have in Christ. She doesn't need a deep theological lecture right now - but she does need to know that God loves her and understands her heartache. Furthermore, He sent His Son into the world to give us hope. These truths will bring comfort to her soul.