Imagine how Moses felt at the end of Exodus 5. He must have considered his mission to be a complete failure. He had come - unwillingly, but obediently - as directed by God to deliver his message to Pharaoh: "Let me people go!" (vs. 1) And how had Pharaoh responded?
Pharaoh asks the same question that Moses did in chapter 3: "Who is the Lord?" Pharaoh insists that he does not know this God of the Israelites, and so he will not let the people go (vs. 2). In fact, Pharaoh makes their labor even worse by determining that the people are lazy. They are now required to get their own straw - but not to lesson the amount of bricks they produce! He asks the impossible, and the people are beaten when they cannot comply.
Sure that there must be some misunderstanding, the leaders of the people go to Pharaoh to explain that they cannot make bricks without straw. The misunderstanding, however, is theirs. Pharaoh accuses the people of being lazy, and his solution to that problem is to make them gather their own straw in addition to their other work. The number of bricks required of them is not reduced in the slightest.
Even though this order comes from Pharaoh, Moses is the one who gets the blame. "You have brought us into bad odor with Pharaoh and his officials, and have put a sword in their hand to kill us," they complain to Moses. (This would not be the last time that the people complain to Moses!)
Moses is disheartened. Turning to God, he cries out, "Why? Why did you send me?" The situation of the people is worse than ever, and Moses feels that God has let him down.
Moses is about to understand, however, that it was never going to be easy. God is going to have to break the hard heart of the Egyptians to win His people's freedom!