I wasn't brought up in a religious atmosphere. I never once went to church with my family but it was shoved down our neck in school. I really can't reconcile predetermination with freewill and final judgement. Hell is an all-too convenient, archaic, tool of coercion. As much as the idea of heaven gives people comfort, hell also gives people comfort; it's nice for them to think those who did not lead, what they perceive to be, as moral a life as their own will suffer for it. Otherwise, what is the point in being moral?
I have had a few experiences in my life where I believed I was dead and had gone to hell (another few where I believed I had died and gone to heaven) and, mostly, they terrified the shit out of me. However, I don't believe it any conscious existence after death, nor do I believe in any judgement of the spirit.
As Curtis Mayfield wrote - ''If there's a hell below, we're all gonna go''.
Despite what I said - I want to tell you that hell is definitely real and you will suffer far more than you currently are

- don't catch the bus, man. I know the hurt is still raw, but she's not worth that. Nobody is. I'm not judging you in any way as I would be a massive hypocrite, but stop with the amount of meth and heroin while everything is still raw. They only feed to the cycle of the compulsive thinking about her, the anger, the guilt, the hindsight. I've reached the stage a few times in my life and I've only ever acted on it when the perceived pain outweighs the guilt. When you don't succeed and have to deal with the aftermath, what you do to your loved ones, then the guilt and shame really hits you.
I know it sometimes doesn't feel enough to preserve your life for the sake of others, but that's a pretty damn good reason if you ask me.
Besides, your uncertainty about hell is a good thing. The question of whether and what there is after death is uncertain. It could be worse. At least the suffering that everyone's guaranteed when they're alive is a familiar suffering. You don't know what you'll get when you die. Don't be tempted with Descarte style thinking of, ''The world only exists as I am here to perceive it''. The world does go on when you're dead. Suicide leaves so many questions for people and that guilt that one overcomes to commit the act gets propagated into far more people.
Speak to someone. Maybe see if you can admit yourself to a psych ward voluntarily. A few weeks away from everything can be a great help, if only to get yourself stabilised a bit. The heartache will get easier, man. Even if it takes a few years, it will. It took me about five years, I'm still a bit scarred but they're scars that don't hurt. Sure you might re-open the wound now and again, but you get much better at repairing it.
Just don't be so hasty. You aren't able to reason properly in your mindset, when you have such powerful drugs being added to the mix.
Get speaking to someone!
