Ok well that rules out cult influence at least from a group situation.
I guess if you dont believe that things can get better then they most likely wont get to that place you dont believe exists.
I didnt believe for a long time myself but i feel much better being me than i did a few months ago let alone years ago when i was way worse and suicidal.
You can be rich and have all the material possesions you want and still be depressed and hopeless.So it really is how you think that makes the biggest difference i believe.Satanism may have shown you the opposite way to think.
When people give encouragement its ment to give you hope.But maybe you need to find your own hope in your own way so that it is yours.If you feel you dont have any it doesnt mean you cant find it.
If you feel you cant accept you might be happy later then maybe you have accepted to be sad instead.How will you find a solution when your still teaching your mind to go for the negative.The possibility or choice of the positive needs to be there for you or it is not an option.
I literally had to choose or force myself to be happy like training a new habit.At the moment im sitting at about 40/60(positive/negative) meaning i can decide at any time im reminded that i can decide to think positive or negative but i default still slightly to negative out of habit.
Maybe you have gone very far in the negative direction but its not too late to retrain your mind i bet.you are still not even 20yet!
I used to think ahead and think how old i will be when im 20 and it seemed sureal when thinking i would get THAT OLD! lol
Now i am 30 and looking back at 20 and thinking holy sh$t i was so young and could have done anything i wantd...if only i had realised at the time.My mind held me back because of my strict religion at that time.I still have old regrets because i didnt act then and i decided to mop arond or just do enough to get me by because i was depressed in my situation.
The key back then for me was i had low self esteem and i didnt even think i had the ability to change my situation.
I hope you dont do as i did and believe you negatve self when it says you cant do that.
People say life can be better because its true.Its just that you need to step up to the plate and make that life happen.
Some things that helped me get my head around accepting life positive and negative is the idea of ying and yang.

When i am thinking back to my dark past i also have this picture in my head.
It helps me remember that it is not only the good positive experiences that makes me a good person but also the bad ones too.
If i reject the black part of that ying and yang or the white part i am not complete and only functioning to half my potential.
Both parts make who i am and because of my differeing experience to ANYONE else in this universe i am a totally unique person as you are.That is just fact not just attempted motivation on peoples part.
You are unique and capable of much much more.you just dont see it or believe it yet.Its up to you if you will have that chance.
Its easy to carry on with habits including ways of being and thinking.It keeps us stable where we are.
For you to change your way of thinking will take work and searching but i think importantly too is belief that it is possible.
I was thinking too.If a religion (satanism) most likely changed your cognitive perceptions maybe buddhism or one of those could help move back to a more positive view as you work on research and yourself(i was a jehovahs witness and had to rehabilitate myself and my views of the world after i left).Doesnt have to be meditation.You can read up on the principles and beliefs.I think you need to do as i did and keepsearching for things that strike a chord in you and that you feel you can relate it to your life and past.You have had a rough past so it could take a while to get to where you want.
By the way how do you want your life to be in 10-13 years? Do you have any goals you want(or even better LOVE) to reach?