Born in an islamic country with an islamic household but am agnostic, similar to you. No one knows what the afterlife is like, it's up to you what you want to believe.
What I do know however is that, if there truly exists a God, he will understand why I came to the choice that I did. And if he is truly all loving, he will forgive me and give me the peace I sought after all my life.
If those things aren't true, then I was fucked from the start really. My suicide is only one of the many things that could get me in hell lol, so I'm really not very concerned about it. Either He'll be good to me, or not. I have no control over the matter.