A couple points need to be made here: there is no god or heaven. I can't be 100% certain of that (nobody can either way), but I'm certain enough to say don't count on it if it makes the thought of killing yourself seem more palatable. Also, these struggles that you're going through at a young age will serve you well down the road. We need some heartache in our lives to truly have the capacity to appreciate the good things in life. If it were all sunshine and happiness we would not have that capacity. You may not understand that now, but you will likely look back on this and view it as a good thing at some point. It can, and should make you a better person if you are open to learning from mistakes and struggle.
I won't pretend to understand where you're coming from, and I won't judge you for it. I can't relate. I have a wife and 3 kids, and I would never consider suicide an option. I wouldn't put my loved ones through that.