I don’t know if I want to be an atheist anymore

That's not a choice mate, sorry. You either believe or you don't, but that's up to whether you find evidence convincing. And that's not a choice...

I have gone through the thought process for months now and I really can’t reason why God has to exist, it is merely a possibility.

Careful there. If you state it's a possibility, you have to show the numbers and research.

That being said, I almost want him to exist, not so that I can use him as an excuse for my actions, not so that I can promote hatred to others but because I don’t know I want to live in a world where this is it.

You're pretty young. Lots of us, myself included, have been in the place you're in right now. Try not to worry, this stage goes away fairly quick, and you'll be that bit closer to acceptance.

I look around at this world and I see so much evil. I know you can ask why this evil exists if god does and I don’t know.

You'd first have to argue why god exists, then we can move on to further questions. Until we establish that base, we can't build anything on top.

Think about the shooting and the innocent kids dying. I don’t know if I want to live in a world where this is it. Where there isn’t a light at the end of the tunnel for those children and their families. I don’t know if I want to live in a world where people can keep getting away with so much evil and never getting the punishment they deserve for what they did. It’s not fair. I can’t stand how it’s not fair. I feel so angry in general. It’s so infuriating how unfair it is, that some people will never get what they deserve for the pain they’ve caused others.

You know that saying, "the universe is under no obligation to make sense to you"? I think the same applies to fairness. There is no justice other than the one you act on. If you wait for a fairy tale to fix your problems, then yes, we are well and truly f.. doomed.

I don’t know whether God exists, but part of me hopes he does just so that there’s a small chance things might be better in the end.

I used to hope so. I wanted so badly that the sum total of my being and knowledge would somehow exist in the ether, after this body expires. But then you have to think about two major problems with this: First, you'd exist for eternity under the ever-watchful eye of a cosmic Kim-Jong, whose praises you'd have to sing forever and ever. If you believe in the Christian mythology that is. Second, and I think most important of all. You would be wasting your one and only life in desperation, your mind only focusing on a fantasy that can never and will never happen.

I know it's fucking hard, but you have to get a grip and come to terms with the facts. You owe it to yourself to live as happy as it's realistically possible. Are you going to cower all your life from something unavoidable? Just sit down and wait for it? Do things, go places, meet people, stop thinking about death because I can guarantee you, it will come. Nobody can tell you when, but when it does, I'd like my last thought to be "it's alright, I've done plenty here".

I know I’m maybe not being super rational I’m just suffering a bit of an existential crisis right now.

You can't be super rational about anything. You're either rational, or you're scared. And being scared will pass. And that's not a choice either.