What ever you have done, however bad you may think you are, however much you think you have no chance to change. If you turn to Allah with sincere repentance
Allah will turn your bad deeds into good ones. [Surah Al-Furqan 25:70]
I know it seems you have done the most horrible unforgivable thing. But the fact you feel like this means your heart is still alive. So don't give up hope. Dont let the shaytaan trick you into thinking there is no way back. As long as the shaytaan doesn't give up trying to mislead you don't give up on making tawbah to the most merciful and trying to change. It is so hard, you feel like the your world is squeezing you and your nafs is inclined to give in to your desires, I know Akhi. I know. Just hang in there. Remember the words of The most forgiving:
Say: O My servants who have transgressed against their own souls, despair not of the mercy of Allah. Indeed, Allah forgives all sins. Truly, He is Most Forgiving, Most Merciful. (Surah az-Zumar 39:53)
Also Lets be merciful to one another, instead of scolding one another, bad mouthing and exposing each others sins.... Let us help and encourage one another and hide each other's sins.
Narrated Jarir bin 'Abdullah: Allah's Apostle said, "Allah will not be merciful to those who are not merciful to mankind."
MAY ALLAH GIVE US THE TAWFEEQ
All praise and glory be to Allah the creator, the sustainer, the enricher, the afflictor, the most merciful, the most forgiving, the All seeing the All knowing.
And abundant peace and blessings be on his slave and messenger Sayeedna, Habinah, Mustafa Muhammed Sallalhu Alayhi wa salam.