When is faith enough?

I just read this article on how we shouldn't rely so heavily on the open door/closed door philosophy of prayer. The article says Satan loves to close and open doors at his will so we need to trust in what God has placed within our heart. If we know that God wants us to do something, that He's designed us to do it, then we need to pursue it and be persistent about it. So-armed with this new insight, I cannot help but wonder at my own circumstances. I really feel like I know what God has for me. And I have asked and asked and asked-talk about persistent! Yet, I am still without. Should this be a sign it is a closed door? At least right now? How do you give something up if you think it's truly just a "not now" response? I mean, if it's not now, you still think it will be sometime in the future, so you keep hope alive when maybe it would be less cruel to just let it die for the time being. I'm not good at this. As a matter of fact, this is the thing I am worst at. I know God sees my heart and I know He sees my circumstance and He knows what I want. But I can't help but feel slightly disappointed that again it's no, at the very least a not now. God-if it's not to be, take it away completely, I'm too destructive to myself. For my sake, close the door completely and guard my heart from the pain I know is coming with this prayer...