Now he who supplies seed to the sower and bread for food will also supply and increase your store of seed and will enlarge the harvest of your righteousness. 2 Corinthians 9:10 (NIV)
You must decide you will look to GOD ONLY as your source of supply. You need to tell God that you're going to look to Him alone to provide for your needs and that you won't look anywhere else.
We get ourselves in trouble when we confuse the channel with the source. God may use your paycheck from work as the channel to supply your needs, but your employer is just the channel for God's provision - and he can shift to another channel anytime he wants.
When you start to look to something or someone else to meet you needs, when you begin to confuse the channel with the source, there is a clear warning sign: Worry!
Say you've started looking to your job as the source, instead of the channel. You may start worrying, "What if I loose my job?" You knoiw what - the channel may have closewd, but the source of your every need is still active and providing for you. When God turns off one channel, He can turn on another one.
Once you know what you're lacking, you need to give God the right to choose whatever channel He chooses to fulfill the need. It may be a channel different than you choose; in fact, God may delieberatly choose a different channel in order to teach you to keep looking to him for all your needs.
I have learned - as a Christian for nearly forty years - that it's exciting to just to let God be God. It's exciting to watch God meet a need in a way that you never thought possible or could have never thought up on your own.
God alone is the source of your supply.