In Islam, it is believed that Allah is the Most Merciful and Forgiving. If you have made a mistake and sincerely repent, seeking forgiveness with a pure heart, it is believed that Allah is ready to forgive those who seek His forgiveness.
The Prophet Muhammad (peace be upon him) said: "Allah, the Exalted, has said: 'O son of Adam, I forgive you as long as you pray to Me and hope for My forgiveness, whatever sins you have committed. O son of Adam, I do not care if your sins reach the height of the heaven, then you ask for my forgiveness, I would forgive you. O son of Adam, if you come to Me with an earth load of sins, and meet Me associating nothing to Me, I would match it with an earthload of forgiveness.'"
So, if you have truly repented and turned to Allah seeking forgiveness, have faith in His mercy and know that He is always ready to forgive those who sincerely seek it.
Regarding your anxiety, there is a powerful dua (supplication) you can recite:
اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْهَمِّ وَالْحُزْنِ وَالْعَجْزِ وَالْكَسَلِ وَالْبُخْلِ وَالْجُبْنِ وَضَلَعِ الدَّيْنِ وَغَلَبَةِ الرِّجَالِ
Transliteration: Allahumma inni a'udhu bika min al-hammi wal huzni wal 'ajzi wal kasali wal bukhli wal jubni wa dalla'id-dayni wa ghalabatir-rijal.
Translation: O Allah, I seek refuge in You from anxiety, grief, weakness, laziness, miserliness, cowardice, the burden of debts, and from being overpowered by men.
Reciting this dua sincerely and regularly, along with putting your trust in Allah and seeking His guidance, can be helpful in managing your anxiety.
Remember that while making dua is important, it's also essential to take practical steps to address any issues causing you distress. If needed, consider seeking support from friends, family, or a professional counselor to assist you in coping with anxiety.
Always turn to Allah in times of need and trust in His wisdom and mercy. Remember that seeking forgiveness, repentance, and making sincere dua are acts that Allah appreciates. May Allah grant you peace, strength, and guidance on your journey.