All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, we ask Allaah not to let your heart deviate after He Had guided you to ‘Eemaan (faith), and we ask Him to prepare for you from your affair right guidance.
We give you glad tidings that whoever repents, Allaah accepts his repentance no matter how great his sin is, Allaah Says (what means): {Say, “O My servants who have transgressed against themselves [by sinning] do not despair of the mercy of Allaah. Indeed, Allaah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.”} [Quran 39:53]
Among the conditions of repentance is to regret your sin, seek Allaah’s Forgiveness for it and be determined not to do it again.
As regards how to repay that loan, then you are only obliged to pay the original amount that you had borrowed, and you are not obliged to pay the interest and it is permissible for you to evade paying it [interest]. You should take the initiative to repay the original amount that you had borrowed, so you should only send the original amount of the loan to the institution that lent you the money as Allaah Says (what means): {But if you repent, you shall have your capital sums. Deal not unjustly (by asking more than your capital sums), and you shall not be dealt with unjustly (by receiving less than your capital sums).} [Quran 2:279] In this verse, Allaah called imposing interest as injustice, and injustice is harm and harm should be removed as per the Sharee’ah rules. Hence, the person who imposes Riba (interest and/or usury) on the borrower is only entitled to his capital sum (of the money he lent) and whatever exceeds this sum is injustice, and not paying him his capital sum is also injustice.
Therefore, you should not deal unjustly and you should not be dealt with unjustly. For more benefit, please refer to Fataawa 86136 and 86521.
Allaah Knows best.