If you were in your friend's shoes, wouldn't you hope someone would care enough about you to share your burden? I suspect you would and that's one reason why you shouldn't turn your back on your friend.
You see, it's hard for any of us to carry our burdens alone. This is why the Bible tells us to "Carry each other's burdens, and in this way you will fulfill the law of Christ" (Galatians 6:2). This "law of Christ" is His command to love others, and when we make life easier for someone by helping lift their burdens, we are obeying His command.
How can you help your friend? First, pray for her. Ask God to encourage her, and ask Him also to give her wisdom to know how to deal with her problems. Pray most of all that she will turn to Christ and place her burdens and her whole life into His hands. The Bible says, "Cast your cares on the Lord and he will sustain you; he will never let the righteous fall" (Psalm 55:22). No problem is too great for God.
Then let her know that you care about her and want to help her by being her friend. Don't feel you have to have a solution for all her problems; sometimes the best thing we can do for someone is to be a good listener. In addition, urge her to share her problems with an experienced adult she can trust her pastor, a school counselor or an older friend.