Exodus 16:27 Now it happened that some of the people went out on the seventh day to gather, but they found none.
When God wants us to do something He is going to provide for us according to what He has asked us to do. If we run off and try our own thing we may well find ourselves a bit stuck!
The people of Israel were given strict instructions to gather enough Mana on the sixth day so they would not have to gather on the seventh day.
When some ventured out on the seventh day they found nothing because that is not what God wanted them to do.
Be careful to listen properly to God to find out the instructions He has given you and not to follow your own will.