Is my lack of success in my studies and work due to my shortcomings in the cosmic laws or the religious laws (sins)? If the reason is sins, is my current misery and lack of success a sign of Allah's wrath?

The believer is tested to ascertain the truthfulness of their faith and to elevate their status. Cosmic causes (such as studying for success) are not exclusive to Muslims, and Allah can suspend them by His wisdom. However, শরعي (Shari'ah-compliant) causes (like Ruqyah and piety) are specific to Muslims. Lack of success might be due to not employing cosmic means, or due to sins, or as a trial, or to avert evil, or to store up good. The believer should be content with Allah's decree and destiny, for true happiness is the happiness of the heart through faith and trust in Allah, and not through abundance of wealth or prestige.