Sometimes we think our sins are as high as like the sky how could Allah forgive us!! it shows the lack of Imaan, Shaitaan (Devil) is whispering He wants to Win, Never give Shaitaan (Devil) the opportunity to win, Remember Allah is the Most Merciful & Kind, Allah forgives all the sins no matter if it is deep as the ocean, so Repent to Allah seek forgiveness, Surely Allah forgive those who repent, In Sha Allah.