You aren't necessarily doing anything wrong; nowhere in the Bible does God promise that all our problems will vanish if we just have a positive attitude about them.
Instead, we are to commit our problems to God and seek His help to overcome them. God loves us and knows the problems we face -- and He knows, too, that we can't solve them completely on our own. We need His help, and even in the face of the most difficult problems imaginable, we can turn to Him in faith and trust. It's not our attitude that's important (although it may help), but our trust in the living God.
Does this mean all our problems will vanish if we only turn them over to God? Sometimes they do, but not always. Sometimes God takes away our problems or helps us figure out ways to solve them, but sometimes He helps us instead by giving us the strength and courage to live through them. But no matter what happens, we can trust Him to do what is best, because we know He "is able to do immeasurably more than all we ask or imagine, according to his power that is at work within us" (Ephesians 3:20).
Is your faith and trust in Jesus Christ -- both for this life and the life to come? If so, you can face the future with confidence and peace and joy, because you know that no matter what happens, you are safely in His hands forever.