How can one get rid of and repent from major sins, and deal with the resulting emotional pain and obsessive-compulsive disorder, in addition to how to deal with romantic relationships at an early age, and control desires, while wishing for righteousness and the forgiveness of sins?

The summary of the answer:

The young man is advised to repel and ignore obsessive thoughts, to consult a psychiatrist if necessary, to abandon the wish for death, and to rid himself of negative emotions. He should cut off communication with the girl, as it angers Allah and hinders him from excelling. As for past sins, one who repents from them is like one who has no sin; he should forget them and start a new chapter. For righteousness, he is advised to associate with the righteous, to constantly remember Allah, to supplicate, to sincerely strive against his lower self, and to fast frequently. If he returns to sin, he should not despair of Allah's mercy, but rather repeat sincere repentance.