When will I be free from the lack of self-confidence, and the fear and anxiety that control my life?

Failing an exam should be a motivation for diligence and hard work, for life is a series of experiences from which we learn. Optimism is good, for in Sunan Ibn Majah, it is narrated from Abu Hurairah (may Allah be pleased with him) that he said: "The Prophet (peace and blessings of Allah be upon him) used to like good omens and disliked evil omens." And the Lawgiver has encouraged us to take hold of the means of strength, for he (peace and blessings of Allah be upon him) said: "The strong believer is better and more beloved to Allah than the weak believer, and there is good in both. Be keen on what benefits you, seek help from Allah, and do not be helpless. If something befalls you, do not say, 'If only I had done such and such,' but rather say, 'Allah has decreed, and what He wills, He does,' for 'if only' opens the door to the work of Satan" (narrated by Muslim). Failure and mistakes happen to many people, but they rise up and benefit from their experience. Seek help from Allah, think well of Him, ask Him for success, and strive.