You're right, up to a point; God hasn't promised to those of us who are believers that we'll be spared from the sufferings and problems of this life. Sometimes we will be -- but not always. Jesus wasn't spared from suffering and death -- and neither are we.
But that doesn't mean it's useless to have faith in God -- not at all. Isn't it better to face life's trials and hardships with God than without Him? Isn't it better to know He is with us to help us than to be totally alone when disaster strikes? Of course it is. Some of the saddest words in the Bible are those that speak of people who are "without hope and without God in the world" (Ephesians 2:12).
Furthermore, when we know Christ, our hope is not in this world alone. Instead, we know that someday all the troubles of this world will be over, and we will be safely with God in heaven forever. And some day all the things we don't presently understand will be made clear. Because of Christ we can have hope -- hope right now, and hope for eternity.
Don't turn your back on God, and don't talk yourself into thinking you don't need Him -- for you do. The greatest discovery you'll ever make is that God loves you and wants you to be part of His family forever. And you can be, as you open your heart and life to Jesus Christ. He alone is our "hope of glory" (Colossians 1:27).