the only one who will never b forgiven is Iblis.
As of to consider Allah name Ar-rahman(most mercyfull)
the glorious Quran is also his message of how mercyfull our lord is and in a hadeess nabikareem (our prophet) says if we take a step asking forgivness from allah allah accepts us by running towards us so sister dont let nything worry you allah might have forgiven you if you repented on your sins so be thankfull to allah taht he made you realise that you were doing wrong
now sister you must understand being saddned by the thought that we might be not forgiven is of Iblis he knows that he did wrong by not bowing at the Allahs command and we also know that we also did wrong by doing something which was not allowed but there is a huge difference between Iblis's sin and our wrong doing WE CAN REPENT IT TO ALLAH ASK HIS FORGIVNESS BUT SATAN DOES NOT CAUSE HE IS PROUDISH
so sis if WE BEG OF FORGIVNESS WE ABSTAIN PROUDISHNESS IN FRONT OF ALLAH AND ALLAH LIKES THAT so never hesitate to ask for forgivness inshaallah THE MOST MERCYFULL WILL SHOW MERCY..
now let me tell you a story which i read in book of tafseer e quran( hope it helps you understand the mercy of allah)
there was a man who was a murderer and he killed 99 people one day he asked himself will allah forgive me and he wanted an answer to that Q so he asked his neighbors about an immam who knows about Allah's attributes they guided him to certain man he came upto immam and asked i have killed 99 people will allah forgive me immam said MIGHT BE NOT he heard that and killed the immam. then he inquired about another immam and went upto him asked the same Q immam replied Y NOT ALLAH IS ever forgiveing but do a thing dont head back to your village as it is very violent and people in your village are not well civilized you dont go their head to this village in this certain area as the people there are very pious and lord fearing people. so the murderer after talking to immam decided he will never head back to his village and will never do anything like that and will go and settle in the village of pious people.
but on the way he died now to take his soul angels arrived one from hell and one from heaven but it was confuseing for them who should take his soul angels of hell argued that he mig have repented but did no good after that and angels of heaven argued that he repented it at least before dying so allah orderd them to measure the length of the earth from the point of his repentance to the village of the pious and if he was closer to village he should be taken by angels of heaven and if not far from repenting point he should b taken by angels of hell and then the angels measured and allah ordered the earth to shrink on one side of the measureing scale and by allahs order land shrinked so did the distance between the village and the muderer was taken a back by angels of heaven.
so sis understand it clearly Allah is ever forgiveing and insha allah allah will bless you with peace and delight in your life grieving is for Iblis not for muslims cause Allah is there to forgive us Allah is there to feed us Allah is there to take care of us