Are you feeling useless? Don't believe it. Even when you feel like you're having no affect on your world, you are. No matter if you say nothing God is shining out of you. And if God is shining out of you, how can there be nothing happening?
Do you hear nothing when you read the Word? Read it anyway.
Do you feel like nothing you say in prayer is being heard? Pray anyway.
Do you feel lost in your walk of faith? Walk anyway.
You aren't lost. Your prayers are being heard. The Word is working in you even when it all feels absolutely empty. God promises His Word always accomplishing what He planned for it to accomplish. So if you read it there is a plan for it to do something in you (by the way if you want to read the verse I am referring to click here).